Data Analysis and Sampling – Flashcards
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In a high school league, there were 256 touchdowns made last year. If 64 games were played, what is the mean, or the average, number of touchdowns made per game
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4
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Sasha wants to know her average grade on her math tests. She earned a score of 70 on two tests, an 80 on one test, and a 90 on two tests. What is Sasha's mean score?
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80
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Brian has 5 marbles, Sarah has 9 marbles, Jimi has 4 marbles, and Juan has 6 marbles. They want to redistribute the marbles so that each person has the same number of marbles. If the marbles are redistributed, then how many should each person get?
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Each person should get 6 marbles
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Steven received scores of 70, 95, and 80 on his last three math tests. He needs a mean test score of 80 to qualify for the math team. How many points does he need on his last test to qualify for the team?
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- Steven needs 320 total points to have a mean score of 80. - Steven has 245 points so far. - Steven needs to score at least 75 points on his last test to qualify for the team.
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Dwight has 3 baseball cards, and Ellis has 9 baseball cards. If Dwight and Ellis put their baseball cards together and then divide them up equally, how many will each one of them have?
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6
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The table below shows the deliveries for Floral World for the week. What is the mean, or average, number of deliveries per day?
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A. 16
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The students in the cooking club brought sugar to class. They each brought 3, 4, 5, 3, and 5 cups of sugar, respectively. They divided the sugar evenly so that each student received the same number of cups of sugar. How many cups of sugar did each student get?
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4
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Monica bowled three games. Her scores were 175, 142, and 133. What was her mean, or average, score?
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150
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Four students found the mean of the data set 26, 31, 39, 30, 16, 16, 18, 38. Which student found the correct mean?
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Ashrita's work
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Maria scored 72, 97, and 82 on her first three math tests. She wants to have a mean score of 82 for the quarter. How many points does she need on her last test to earn an 82 for the quarter?
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77
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The table shows the attendance at the art show for the past week. What does the attendance need to be on Saturday to have an average attendance for the week of 30 people per day?
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50
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George sold 18, 22, 26, 12, 25, 20, and 19 cars per month over the past seven months. He followed the steps below to determine the number of cars he needs to sell in the next month to have a mean number of sales per month of 24.
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Step 1
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Asa received scores of 72, 97, and 82 on her last three math tests. She needs a mean test score of 82 to qualify for the math team. What is the first step in determining how many points she needs on her next test to qualify for the team?
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Determine how many total points are needed to have an average of 82.
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What is the mean of the data set? 17, 24, 26, 13
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20
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Relatives gave Timothy $15, $50, $25, and $18 for his birthday. What is the mean amount of money relatives gave Timothy for his birthday?
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The mean amount of money relatives gave Timothy was $27
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Which statements are true about the median? Check all that apply.
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- Put the values in numerical order before trying to find the median. - The median is the number in the middle of an ordered set of values. - The median must be calculated by finding the mean of the two middle points when there is an even number of data points.
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Find the median of each set of data. - 12, 8, 6, 4, 10, 1 - 6, 3, 5, 11, 2, 9, 5, 0 - 30, 16, 49, 25
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- 7 - 5 - 27.5
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Derrick needs to figure out how he's doing on his test scores so far this year. You can help by calculating the mean and the median to get an overall picture of his scores. Below are all of his scores: 25, 40, 68, 85, 95, 98, 70, 78, 85, 100
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What is Derrick's mean test score so far? 74.4 What is Derrick's median test score so far? 81.5 Which gives a better picture of his scores? median
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Journalists try to use shorter or simpler words in their news stories whenever possible. The box below shows the number of letters in each word taken from one sentence in a news article. What are the mean and median number of letters per word? What is the outlier?
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The mean number of letters per word = 5 The median number of letters per word = 4.5 The outlier = There is no outlier
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Zahra was given two data sets, one without an outlier and one with an outlier. Data without an outlier: 15, 19, 22, 26, 29 Data with an outlier: 15, 19, 22, 26, 29, 81 How is the median affected by the outlier?
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The outlier slightly affected the median.
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Which set of data contains two outliers?
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101, 135, 131, 99, 138, 136, 140
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Deepali was given two data sets, one without an outlier and one with an outlier. Data without an outlier: 15, 19, 22, 26, 29 Data with an outlier: 15, 19, 22, 26, 29, 81 How is the mean affected by an outlier?
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The outlier made the mean higher than all the other values.
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What is the median of this set of data? 1, 2, 5, 6, 9
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5
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Noah was asked to find the median of the following numbers. 115, 109, 117, 136, 127, 131 Noah's work is shown below. What error, if any, did Noah make?
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He did not make any error.
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What is the median of this set of data? 66, 51, 77, 68, 60, 75, 54, 80
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67
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Sasha's daily tips this work week were $43, $32, $65, $88, $50, and $72. Is Sasha correct in thinking that the mean accurately represents how much money she makes in daily tips?
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Yes, Sasha is correct. The mean amount she makes is $58.33 in a day.
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Eva earned the following test scores in science: 82, 100, 96, 90, 91 Ms. Wade entered the next score as 0 because Eva was absent on test day and hadn't had a chance to make up the test. Which statements are true based on the data? Check all that apply.
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- After adding the 0 test score, the mean would be affected. - After adding the 0 test score, the median would be the most appropriate measure of center to describe the data. - Before the missed test, Eva's median score was 91. - Before the missed test, Eva's mean score was 91.8.
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Peter's teacher says he may have his report card percentage based on either the mean or the median and he can drop one test score if he chooses. 84%, 71%, 64%, 90%, 75%, 44%, 98% Which measure of center should Peter choose so he can have the highest percentage possible?
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Peter should choose the mean after dropping one test score.
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Ari's teacher says he may have his report grade based on either the mean or the median of his last six test scores. 88%, 73%, 97%, 76%, 90%, 80% Which measure of center would best represent Ari's grade?
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both the mean and the median
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Which of the following are measures of spread? Select all that apply.
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- Range - Interquartile range - Quartiles
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Which statements are true about the interquartile range? Select all that apply.
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- Interquartile ranges are not significantly impacted by outliers. - Lower and upper quartiles are needed to find the interquartile range. - The data values should be listed in order before trying to find the interquartile range.
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What do you know about this data before finding the range or the interquartile range? 187, 191, 202, 209, 218, 1984
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The data has an outlier, therefore the range will be much greater than it would be without the outlier.
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Find the median, range, and interquartile range of both sets: Set 1: 65, 66, 77, 79, 81, 93, 104, 105 Set 2: 56, 1, 29, 72, 67, 59, 74, 60 Which is true about the two sets?
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Both sets have an interquartile range of 27.
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Use the data set to determine which statements are correct. Check all that apply. 35, 41, 18, 75, 36, 21, 62, 29, 154, 70
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- The median is 38.5. - There is an outlier. - The lower quartile is 29. - The upper quartile is 70. - The interquartile range is 41.
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Which describes how to calculate the range of this data set? 4, 5, 6, 8, 11, 12
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Subtract 12-4
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What is the range for this set of data? 38, 17, 55, 40
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38
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What is the interquartile range of this set of data? 15, 19, 20, 25, 31, 38, 41
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19
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What is the upper and lower quartile of this set of data? 15, 19, 20, 25, 31, 38, 41
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lower quartile: 19 upper quartile: 38
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Kate recorded the number of minutes she read each day for the last two weeks in the table. How can Kate figure out which week had the larger range in minutes read?
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1. Order the minutes for each week. 2. Find the range for each week. 3. Compare the ranges. Week 1 had the larger range in minutes.
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Eight car dealerships reported the number of cars they sold last month. What is the interquartile range of this set of data?
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C. 12.5
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What is the range for this set of data? 7, 15, 12
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8
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Harlon recorded this set of data, which contains an outlier. 163, 97, 184, 199, 169, 175 What is the range of this set of data?
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102
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Kwan recorded two sets of data. Set 1: 9, 13, 6, 18, 15, 19, 20 Median: 15 Lower Quartile: 9 Upper Quartile: 19 Range: 11 IQR: 10 Set 2: 9, 13, 6, 18, 15, 19, 20, 63 Median: 16.5 Lower Quartile: 11 Upper Quartile: 19.5 Range: 54 IQR: 8.5 One set of data shows an outlier. Which measure of spread was most impacted by the outlier?
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range
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Kellan collected two sets of data and recorded them in the table. Which set has a wider spread, and what is the range?
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Set 2 has a wider spread and has a range of 27.
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Swati recorded this data set, which contains an outlier. 163, 97, 184, 199, 169, 175 What numbers represent the lower and upper quartiles?
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lower quartile: 163 upper quartile: 184
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Cheryl wants to find the number of hours seventh-graders do homework each week. There are 297 girls and boys in seventh grade. Which is the best way for Cheryl to get a representative sample without spending too much time?
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She can randomly survey 50 seventh-graders in the school.
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Maridel wants to find out how many of her classmates plan to come to the next football game. There are 800 students in her school. She selects a sample of the population by putting the names of every student into a bag and drawing out 100 names.
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- Her method will produce a valid sample. - Her method will produce a random sample. - Her method will produce a representative sample.
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Which gives the best definition of a representative sample?
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A sample that has the same general characteristics of the target population.
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Suppose you want to know whether the eighth-grade music students at a school spend more time practicing their instruments or playing computer games. Explain how you would get a representative sample from the population. Write three to four sentences.
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Sample response: Get a list of all the music students in the eighth grade. Randomly select enough students to get a sample from the population. Ensure that the selection is completely random so the sample is not biased.
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Nathan and Jordan design surveys to determine the amount of time bicyclists in a race spend training each week. Nathan surveys every fifth bicyclist crossing the finish line after a race. Jordan surveys the first five bicyclists to finish the race. Which best explains which sample is likely to be the most valid?
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Nathan's because his sample was more random
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Kari plans to sample 20 people of a population that contains 100 students. She wants to determine how many people wake up before 6 a.m. Which sample is the most random?
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5 students out of each of the 4 homeroom classes
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Chelsea wants to determine the number of people in her school who read news reports on the Internet daily. She asks five people in her language arts class. Which improvements could Chelsea make to her sample to increase the validity of the results? Check all that apply.
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- increase the sample size - choose students from different grade levels - choose every fourth student in all language arts classes
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Which best describes a random sample?
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a sample in which the elements are chosen by chance
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Lamont designs a survey of town residents in an attempt to predict who will be elected mayor. He chooses his sample of 500 people from the town's 40,000 residents by asking his question to every person leaving the public library on a Saturday. Which suggestion would most improve Lamont's random sample?
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Lamont should sample only registered voters.
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A random sample of people is chosen to participate in a survey. For the survey results to be considered valid, which must be true of the random sample?
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The sample must represent the target population.
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Mikayla designed a survey to determine the number of people expected at opening night of a community theater. The community has about 5,000 members. She selected a sample of the first 25 parents dropping off actors during theater rehearsal. Which best explains Mikayla's sample?
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nonrandom and biased
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Students are voting on the color of T-shirts to wear on their field trip. There are 160 students-65 boys and 95 girls-going on the field trip. A random sample of students is chosen. Surveying the random sample produced a representative sample of the population. Which was most likely true of the representative sample?
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The representative sample contained more girls than boys.
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Samantha and Luis are attempting to determine how many library books each seventh grade student checks out at the same time. Samantha surveys every other seventh grade student leaving the library. She samples a total of 40 of the 200 seventh graders. Luis samples 30 of the 200 seventh grade students at random in the school cafeteria. Whose sample is the most random?
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Luis because his sample is taken from the population of all seventh graders
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Charles wants to find out if the students in foreign language classes spend more time in class speaking in English or in the foreign language they are studying. Charles first gets class lists of all students taking foreign language classes. He then chooses 10 students from each different language class to survey. Which best explains why the sample he chose may not be a representative sample?
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NOT The sample size is not large enough to represent the population.
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Great Granola makes a trail mix consisting of peanuts, cashews, raisins, and dried cranberries. The trail mix sells for $3.50, and the most expensive ingredient is the cashew. The production manager takes a random sample of 15 bags of trail mix from two factories to determine the amount of cashews in each bag. What statistical information could be useful to the production manager? Check all that apply.
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- the average amount of cashews per bag to determine average cost - the amount of variation in ounces of cashews in the bags of trail mix - which factory produces the most consistent ounces of cashews in each bags of trail mix
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Robin and Evelyn are playing a target game. The object of the game is to get an object as close to the center as possible. Each player's score is the number of centimeters away from the center. Robin and Evelyn's results from five rounds are shown. Robin's scores: 99, 108, 102, 107, 119 Evelyn's scores: 125, 137, 138, 145, 145 The mean of Robin's scores is 107. What is the mean of Evelyn's scores?
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138
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Robin and Evelyn are playing a target game. The object of the game is to get an object as close to the center as possible. Each player's score is the number of centimeters away from the center. Robin's mean is 107, and Evelyn's mean is 138. Compare the means. Explain what this comparison indicates in the context of the data. Who is winning the game? Why?
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Sample Response: Evelyn has the greater mean. It indicates that, on average, her objects landed farther away from the center than Robin's. This difference means that Robin is winning the game.
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Tyrell recorded his science scores and his math scores. The measures of center and variation for each score are shown in the table below. Which inference can be made when analyzing the data in the table?
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There is more variation in the science scores.
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The means and mean absolute deviations of the individual times of members of two relay swim teams are shown in the table below. The difference of the means is found and then compared to each of the mean absolute deviations. Which is true?
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The difference between the mean times is about 2 times the mean absolute deviation of the data sets.
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Joaquin and Trisha are playing a game in which the lower median wins the game. Their scores are shown below. Joaquin's scores: 75, 72, 85, 62, 58, 91 Trisha's scores: 92, 90, 55, 76, 91, 74 Which supports the conclusion that Joaquin won the game?
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Joaquin won because the median of his scores is 73.5 and the median of Trisha's scores is 83.
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The means and mean absolute deviations of Sidney's and Phil's grades are shown in the table below. Which expression represents the ratio of the difference of the two means to Sidney's mean absolute deviation?
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4/3.28
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Last week's and this week's low temperatures are shown in the table below. Which measures of center or variability are greater than 5 degrees? Check all that apply.
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the mean of this week's temperatures the mean of last week's temperatures the range of this week's temperatures the range of last week's temperatures
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Two months ago, the mean daily rainfall in a local city was 9.4 cm. The mean absolute deviation was 3.5 cm. Last month, the mean daily rainfall in that city was 11.5 cm, and the mean absolute deviation was 1.6 cm. Which statement about the rainfall is true?
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Last month, the amount of rain that fell each day varied less than the month before.
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Enzo and Zahra are playing a game. Their scores for five games are shown in the table below. Enzo's mean score is 44. Zahra's mean score is 38. The difference between the mean scores is about how many times the mean absolute deviation of the data sets, to the nearest whole number?
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1
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The means and mean absolute deviations of the amount of rain that fell each day in a local city, last week and this week, are shown below. Which expression compares the difference of the two the means to this week's mean absolute deviation?
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0.8/0.5
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Theo recorded the means and mean absolute deviations of his language arts and Biology scores. He found the difference in the means of the scores of the two subjects. What is the approximate ratio of the difference in the means to each of the mean absolute deviations?
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NOT 18 Not 5
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Georgina likes to read during her summer break. The table below shows the number of pages in each book she read last summer and the number of pages in each book she read this summer. What inference can someone draw about the data?
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NOT The books she read this summer had more pages, on average, than last summer. NOT Last summer, the average book had nearly twice the number of pages than the average book has this summer.
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Souta wants to compare the mean of his french scores to the mean absolute deviation. He uses the steps below to find both the mean and mean absolute deviation. In which step did Souta make the first error?
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Step 3
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Darius and Barb are playing a video game in which the higher score wins the game. Their scores are shown below. Darius's scores: 96, 54, 120, 87, 123 Barb's scores: 92, 98, 96, 94, 110 Barb says that she is the winner. Darius says that it is a tie. Who is correct?
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Darius is correct if only the median score is considered.
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Jillian and Dawn are playing a game of miniature golf. In this game, the score on a hole is the number of putts it takes to get the ball into the hole. After playing 18 holes, Jillian's mean is 2.4 and Dawn's mean is 3.3. Which explains who won the game?
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Jillian won the game because the person with the lower mean took fewer putts on average for each hole.
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Polina's math scores are shown in the table. What is the mean absolute deviation of her math scores?
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8.8
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Which is true of a population in a statistical survey? Check all that apply.
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- A population can be a group of objects or events. - A population must be the target of the survey question.
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Which statement is true of an appropriate sample of a population?
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A sample must be a group of people who are the target of the survey question.
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Eric wants to find out the most popular after-school activity among high school seniors at his school. What is the population in Eric's survey?
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all high school seniors at Eric's school
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Determine the best survey question for a population of all cell phones produced by a company.
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What percentage of cell phones made by the company are defective?
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In what situations is it helpful to use a sample of a population? Mark all that apply.
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- if the population is very large - if it would take a lot of time to survey the entire population - if it would require a lot of money to survey the entire population
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A farmer wants to find out the average number of apples produced by the apple trees in his orchard. Which could be a sample of the population?
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some of the apple trees in the farmer's orchard
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Kanesha wants to find out if people in her community would support a dog park. Which populations would be appropriate to sample for the survey?
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People shopping at local pet store.
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Alan is conducting a survey to find out the type of art preferred by students at the town's high school. Identify the population of his survey and describe a possible sample of the population.
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The population of Alan's survey is all the students at the town's high school. The sample must be representative of the population. A possible sample would be an equal number of freshman, sophomores, juniors, and seniors.
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A middle school contains sixth, seventh, and eighth graders. Each grade level contains approximately the same number of students. The principal wants to find the answer to a survey question affecting each student in the school. He asks a sample group "What time do you get up in the morning?" Which of these characteristics define the best sample?
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an equal number of students chosen at random from each grade level
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A survey is targeted at 12-year-old children. Which questions are appropriate for the population? Choose all that apply.
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- Where is your favorite vacation spot? - What is the last book you read?
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A nutritionist wants to know how the taste of artificial sweeteners impacts food choices of diabetic patients. From which group would it be best to take a sample?
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all diabetic patients
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Residents in a neighborhood determine the approximate number of dandelions in each yard. Then, they treat some yards with a weed-killing substance. The residents want to answer the question "About how many dandelions are in your yard?" to determine the effectiveness of the weed killer. From which group would it be best to take a sample?
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all residents of the neighborhood
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A seventh grade teacher asks her students a survey question. Which questions are appropriate for the teacher to ask her population? Choose all that apply.
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- How many hours of sleep do you get per night? - On average, how long does it take you to complete your homework? - What time do you leave for school in the morning?
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Traverion wants to find the answer to the question "How much money does the average college professor make?" He surveys 50 professors from the university in his hometown. Which best describes whether or not the results of his survey would represent the responses from the entire population of college professors?
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The results do not represent the population because the sample does not represent professors from different areas.
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Amalie wants to know if students in her class prefer hot dogs or hamburgers. Why should Amalie survey the entire population rather than a sample of the population?
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The population is small enough to survey the entire group.
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A researcher wants to develop a product for families who have small children. He needs to determine if there is a nationwide interest in a toy that will help children describe their emotions. He asks only a sample of the population to complete his survey. What should be true of the sample so that the results of the survey can be used to predict the results of surveying the population?
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The families included in the sample should represent the families in the population.
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An insurance company is trying to determine the number of texts sent daily while driving. Which best describes the population?
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licensed drivers who own cell phones
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A supervisor wants to know the average number of hours worked by employees in a factory. There are 18 managers, 240 laborers, and 54 administrators. Three managers are chosen to participate in the survey. In order for the sample to accurately represent the population, about how many administrators should be chosen?
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9
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There are 850 employees at a software company. The company's CEO was interested in finding out if his employees prefer the new coffee brand provided in the break rooms or the old coffee brand. A random sample of 200 employees was conducted, and 148 employees said that they prefer the new coffee brand over the old one. The point estimate is calculated using the formula p=x/n Which statements are true about estimating the population proportion of employees who prefer the new coffee brand? Check all that apply.
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- The best estimate of the population proportion is p = 74%. - The value of x is 148.
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Sharon's town has 790 households. She wanted to find out how many of them turn out the lights on Halloween each year to avoid visitors. She randomly surveyed 150 households in various neighborhoods. Out of the 150 households she surveyed, 35 of them said they turn out the lights each year on Halloween. To the nearest percent, the estimated population proportion of households that turn out the lights each year on Halloween is
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23%
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The results of a recent poll of 8,500 randomly selected Americans show that 58% are planning to vote for candidate B in the upcoming election. Candidate B would like to know, within a 95% confidence level, what the maximum expected difference is between the true population parameter and the estimated population parameter. (95% confidence level = z*-score of 1.96) What is the margin of error for this poll? Round your answer to the nearest tenth.
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1%
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A major newspaper conducted a random survey of 1,800 of its 75,000 subscribers. The subscribers were asked if the paper should increase its coverage of national news. Out of the 1,800 in the sample, 594 responded that they want more national news. Construct a 95% confidence interval (z*-score = 1.96) for the proportion of subscribers who would like more national news coverage.
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The estimated population proportion, p , is 33% Margin of error is 2.2% With 95% confidence, it can be said that the proportion of subscribers who would like more coverage of national news is between 30.8% and 35.2%
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A recent poll of 380 randomly selected Americans showed that 24% (p = 0.24) are happy with their cell phone carriers. The country's largest cell phone carrier would like to know, within a 90% confidence level, the margin of error for this poll. (90% confidence level z*-score of 1.645)
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To the nearest tenth of a percent, the margin of error for the poll is 3.6%
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Giorgio surveyed 45 randomly selected shoppers at the mall and found that approximately 24% believe that the food court needs to be remodeled. To the nearest percent, with a confidence level of 99% (z*-score 2.58), what is the confidence interval for the proportion of shoppers who believe the food court needs to be remodeled?
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between 8% and 40%
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Hugo polled 100 randomly selected people to see if they had exercised that week and found that 85% said they had. Lily asked 400 randomly selected people the same question and found that 85% of them also responded that they had exercised that week. If Hugo and Lily use a 99% confidence level (z*score of 2.58), which statement is true?
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Hugo's margin of error will be exactly 2 times as large as Lily's margin of error.
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Sameer polled a random selection of 120 of the 250 workers at his office to determine whether they were satisfied with their office supply ordering process. The survey showed that 90 of the workers polled were satisfied. With a desired confidence level of 99%, which has a z*-score of 2.58, what is the margin of error of Sameer's survey?
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10%
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Katrina randomly selected 64 students out of her school of 400 students and found that 40 of them want school to start at a later time. With a desired confidence of 99%, which has a z*-score of 2.58, which statements are true? Check all that apply.
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- The sample size is 64. - The point estimate of the population proportion is 0.625. -The margin of error is approximately 16%.
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Ivan surveyed 49 randomly selected players from the 134 players of the soccer club teams to see if they wanted the games to be played on Saturdays or Sundays. Twenty-two of the players said that they preferred that the games be played on Saturdays. Ivan correctly determined that the margin of error, E, of his survey using a 99% confidence interval (z*score 2.58) is approximately 18% What is the 99% confidence level for players who prefer the games be played on Saturdays?
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between 27% and 63%
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A prior study determined the point estimate of the population proportion as 58% ( = 0.58). The analysts decide to conduct a second study on the same topic and would like its margin of error, E, to be 4% when its confidence level is 95% (z*-score of 1.96). What is the minimum sample size that should be used so the estimate of will be within the required margin of error of the population proportion?
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585
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A recent poll of 85 randomly selected cable subscribers found that 39% would be willing to pay extra for a new nature channel. To the nearest percent, with a confidence level of 95% (z*-score 1.96), what is the confidence interval for the proportion of cable subscribers who would be willing to pay extra for the new nature channel?
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between 29% and 49%
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The equation for the line of best fit for a data set is y = 2x + 1.5. If the point (1, 4) is in the data set, what is the residual of 1?
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0.5
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Galton attempted to mathematize the work done by his famous cousin
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Darwin
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Galton's study enlisted the help of his friends to grow His study lead to the mathematical notion of
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sweet peas regression
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A farmer harvests apples that are heavier than the average 5 kg weight for that variety. He plants the seeds from the harvest hoping that the next generation will produce even heavier apples. Using the results found by Galton, which statement is most likely true regarding the weight of the next generation?
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The next generation will weigh less than the parent generation, closer to 5 kg.
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What did Galton use to calculate how strong the relationship was for the line of best fit?
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the correlation coefficien
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The quadratic regression graphed on the coordinate grid represents the height of a road surface x meters from the center of the road. What does the graph of the regression model show?
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The height of the surface decreases from the center out to the sides of the road.
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Jessica plots the data points relating the amount of money she needs to repay a loan and the number of months she has been making payments. She calculates two regression models. Which is true?
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The linear model better represents the situation because the amount she owes is decreasing by about the same amount every 6 months.
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The graph shows the data points in the table and the exponential regression model associated with the data. Based on the graph of the regression model, which is true?
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The number of weeds is decreasing by a multiplicative rate.
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The data in the table represents a company's profit based on the number of items produced. Which equation best represents the data?
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y = -1.026x2 + 1016.402x - 162075
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The function f(t) = 349.2(0.98)t models the relationship between t, the time an oven spends cooling and the temperature of the oven. For which temperature will the model most accurately predict the time spent cooling?
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300
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If Amelia wants to make the maximum amount of money working only 22 hours per week, which company should she work for? Explain your answer.
answer
Company B: Using linear regression models from both data sets, she determines that it pays about $10 more.
question
Janna is making a prediction of the frequency of a key that is 12 keys from middle C Which best describes her prediction?
answer
extrapolation, because a key that is 12 keys from middle C is outside the data set
question
The table shows the estimated number of lines of code written by computer programmers per hour when x people are working. Which model best represents the data?
answer
y = 26.9x - 1.3
question
The table shows the wavelength of the sound produced by keys on a piano x keys away from the A above middle C. Using the exponential regression model, which is the best prediction of the wavelength of the key that is 8 above the A above middle C?
answer
49.44
question
Lawrence performs a survey to determine the number of minutes of exercise seventh-grade athletes get in one week. He gets a list of sports and the seventh-grade students participating in each sport. He then chooses 10 people from each list to complete the survey. How can Lawrence's sample be improved to be more representative of the population?
answer
He can choose his sample from every third person on each list rather than 10 people.
question
Ten people reported the number of hours they worked last week. 17, 42, 40, 35, 24, 20, 30, 32, 25, 38 What is the median, lower quartile, upper quartile, and interquartile range of this set of data?
answer
median: 31 lower quartile: 24 upper quartile: 38 interquartile range: 14
question
Denise and Sandra are playing a target game. The object of the game is to get an object as close to the center as possible. Each player's score is the number of inches away from the center. Their scores are shown below. Denise's scores: 112, 116, 125, 119, 131 Sandra's scores: 124, 120, 110, 126, 118 Which explains who is winning the game?
answer
Sandra is winning because she is generally closer to the center.
question
Kai, a seventh grader, wants to determine the average number of times the families in his neighborhood visit the pool during the summer. He samples the families of four of his classmates. Which improvements could Kai make to his sample to increase the validity of the results? Check all that apply.
answer
- sample more families - sample families that have children who are not in seventh grade - sample families living in every third house in the neighborhood
question
Sarah randomly selected 80 shoppers at a grocery store to taste two different types of Greek yogurt. Yogurt brand B was chosen as the favorite by 53 of them. To the nearest percent, what is the 95% confidence interval (z*-score 1.96) for the proportion of shoppers who tasted the two types of yogurt and preferred brand B?
answer
between 56% and 77%
question
When is choosing a sample from a population least likely to be appropriate? Choose all that apply.
answer
- when the population is small - when the sample contains proportions of items/events/people that are different from those of the population
question
Nia recorded her science and math scores. The measures of center and variation for each score are shown in the table below. Which inferences can be made when analyzing the data summary in the table? Check all that apply.
answer
- Her mean science score is higher than her mean math score. - There is more variation in her math scores. - Her median scores are the same for each subject.
question
A town's athletic league contains 18 baseball teams. The board members of the league want to survey adults attending games to determine if they believe the athletes are showing good sportsmanship. The board members attended one game and surveyed an equal number of adults supporting each of the two teams. Which best explains the validity of the results?
answer
invalid because of biased sampling
question
Lydia collected two sets of data. One set of data shows an outlier. Which set has an outlier, and which number is the outlier?
answer
Set 1 contains an outlier. The outlier is 51.
question
The high temperatures in Montana are recorded for a week. What is the mean, or average, high temperature for the week?
answer
52 degrees
question
What is the median of this set of data? 362, 187, 211, 298, 331, 250, 347, 199
answer
274
question
The heights of the starting players on each of two basketball teams are shown in the table below. Jacob found that the mean height of Team A is 71 and the mean height of Team B is 72. He believes that because Team B has a greater mean, it also has a greater mean absolute deviation. Which explains Jacob's error?
answer
Both of the means are correct, but the reasoning is incorrect.
question
Vickie conducts a survey of home builders to determine the average cost of building a new home. She samples 10 home builders who are building in the town in which she lives. Under which conditions will her sample be a representative sample? Check all that apply.
answer
- The builders were chosen at random. - The population included only builders who build in Vicki's town.
question
The mayor of Gilbert, AZ, randomly selects 300 of its residents for a survey while the mayor of Camp Verde, AZ, randomly selects 100 of its residents and asks them the same question. Both surveys show that 15% of the residents of each town want Arizona to start using daylight savings like most of the rest of the country. If the confidence level for both surveys is 95% (z*-value 1.96), then which statement is true?
answer
The margin of error for the Camp Verde survey will be between one and three times as great as the margin of error for the Gilbert survey.
question
Julian and Nina are playing a game. Their scores for five games are shown in the table below. Which statement comparing the medians to the ranges is true?
answer
The medians differ by 3, but the ranges differ by 10.
