105 questioned Stats Review – Flashcards
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A set of Data has a mean that is much larger than the median.
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A stemplot of the data is skewed left
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Interscholasic Sports, Intramural Sports, or No Sports
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Juniors have the highest percentage participation
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AP Scores
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Median is 3
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Birth Rate Median
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110
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40 of the birth weights
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102
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The number of children with birth weights between 102-122
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50%
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Strongly Skewed to the left. Which combo of measure of center and spread?
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Median and IQR
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Lobster fisherman
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14
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Roughly locate the mean of a density curve by the eye because
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it is the point at which the curve would balance if made of solid material.
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Roughly locate the median of a density curve by the eye because it is
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The point that divides the area under he curve into two separate parts
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You are told your score on the exam is at the 85 percentile
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Your score was equal to or higher than approximately 85% of the people who took this exam.
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Mr. William's calculus class
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79%
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Pisaster arm length
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median - 15.2 IQR - 4.3
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A Standard Score Describes
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How far a particular score is from the mean
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Jack and Jill
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Jack - 1.07 Jill - 1.11 Jill Wins
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A data set is Normally distributed with a mean of 25 and Standard Deviation of 8. If you calculate the standard score of every observation in this data set, what will the mean and Standard deviation of the resulting Scores be
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The mean of 0 Standard Deviation of 1
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if 30 is added to every number on the list, what DOES NOT change?
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Standard Deviation
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Standard deviation of salaries
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Increase by 3,000
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The IQR of the salaries for the employees
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be unchanged
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The z scores of the salaries for the employees will
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be unchanged
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Birthweights at a local hospital have a norm dist. with a mean of 110
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.136
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IQ's among undergraduates at mountain tech are...
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5
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A company produces ceramic floor tiles
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.3085
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the time to complete a standardized exam
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78.4
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You are chatting with the principal of a local high school
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M = 550 SD = 75
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Etymologist Heinz Kaefer
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310
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Basketball - Total Assists
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The distribution is skewed
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The response variable
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the volume of lumber
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Which of the following Statements are supported by the scatterplot
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I II III
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Two variables are said to be negatively associated if
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when above average values of 1 variable are associated with below average values of the corresponding Variable
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Correlation coefficient measures
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the strength and direction of a linear relationship between two variables
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Stopping distance vs. outside temperature... Correlation
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Approx. 0.6
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Stopping distance vs. outside temp...if another data point
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Decrease since this new point is an outlier that does not follow the pattern in the date.
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Intercept of Least Squares regression line is approx
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1.8
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Based on the scatterplot the least squares line would predict that a car that emits 10 grams of CO per mile driven would emit approx. how many grams of nox
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1.1
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The point indicated by the open circle
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has a negative
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Least Squares in the term Least Squares Regression line refers to
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minimizing the squares of all the values of the response variable.
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Which of the following statements are true about the least squares regression line
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I II III
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Suppose we fit the LSR line to a set of data. If a plot of the residuals show a curve pattern
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the model is not appropriate
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If removing an observation
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influential
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Suppose a straight line is fit to data having
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Extrapolation.
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The circled point on the scatter plot represents lima beans, which have 621 calories
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-4.18
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Expected average error - LSRL Lima Bean
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3.37648
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A study of child development measures the age
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the test scores gets down by 1.3 pts
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equations - eggs
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Eggs = -142.74 + 39.25Length
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Predicted y-values from the actual y-values
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25.55
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You want to know the opinions of American school teachers... The population is
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2500 teachers chosen at random
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A television station
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Voluntary Response Bias
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a news release
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biased, overstating effect of diet
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A simple random sample of size n is defined to be
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A sample of size n chosen in such a way that every set of n units has an equal chance to be the sample actually selected.
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In an experiment an observed effect so large that it would rarely occur
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Statistically significant
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Another correct label for 816 students
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01-815 ID
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A public opinion poll in ohio
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Stratified random sample
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Stratified random sample addresses the same issues as
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block design
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In the late 1990's Scotland was considering independence from England
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the wording of the question
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frequently, telephone poll takers call near dinner time
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nonresponse
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Which of the following is not a major principle of good design for all experiments
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blocking
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The essential difference between an experiment and an observational stud that
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an experiment imposes treatment on the subject, but an observational study does not
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The reason blocking is sometimes used in experimentation is to
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reduce variability arrising from random assignment
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The probability that the next five babies are girls is
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.03125
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The probability that at least one of the next three babies is a boy
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.875
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The events A = the nest two babies are boys, and B = the nest two babies are girls are
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disjoint
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In a certain town...
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30%
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Suppose A and B are independent events with P(A) = .2 and P(B) = .4
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.12
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The probability your score 4 points both times is
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.0277
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P(A u B) ------ Red and Green
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5/6
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The event corresponding to the system failing during one period of operation is
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F;G
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Event A occurs with a probability of .8. The conditional probability that event B occurs, given that A occurs is .5
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.4
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Event A occurs with probability of 0.3 and event B occurs with probability of 0.4. If a and B are independent, we may conclude that
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all of the above
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The card game Euchre uses a deck with 32 cards: Ace, King, Queen, Jack, 10, 9, 8, 7 of each suit.Suppose you choose one card at random from a well-shuffled Euchre deck. What is the probability that the card is a jack, given that you know it's a face card?
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1/4
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Probability that the student has breakfast
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.5
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Given that the student who ate breakfast is selected what is the probability he is male
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.64
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Find P(B|F) and write in words what this expression represents
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The probability that the student ate breakfast given that she is female
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P(AuB)
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Q + S + R
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P(AnB)
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r/(q+r)
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If a single student is selected at random and you know she has a dog. What is the probability that she also has a cat
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0.75
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If two students are selected at random, what is the probability that neither of them has a dog or cat
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.548
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Let X be the outcome of rolling a fair six-sided die. P(1<X<5)=
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.5
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An expression the represents the probability of at least one tail is
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P(x<3)
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The probability of at least one tail is
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.9375
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In a particular game, a fair die is tossed. If the number of spots showing is either 4 or 5 you win $1, if the number of spots showing is 6 you win $4, and if the number of spots showing is 1, 2, or 3 you win nothing. Let Xbe the amount that you win. Use Scenario 6-2. Which of the following is the standard deviation of X?
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1.41
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The probability that a random scratch card will pay off is
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.0601
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The expected pay off per card
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.85
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The mean number of customers that make a purchase during the first hour that the store is open
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3
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The density curve for a continuous random variable X has which of the following properties
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All of the above
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P(X>400$) is
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.2119
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The probability is approximately 0.6 that on a randomly selected day the store will make less than which of the following amounts
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$372.60
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Albert - What is the expected value of Z
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1.2
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Alberts Game- Standard deviation and mean
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M = 1.6 SD = 1.2
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What is the expected value of T
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40
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Typically the formula 1.07
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m = 42.78 sd = 6.09
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The distribution of X = the number of questions the student will correct is
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binomial with parameters n = 20 and p = 0.25.
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Which of the following expresses the probability that the student gets no questions correct?
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.75^20
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A college basketball player makes 5/6 of his free throws. Assuming free throw attempts are independent, the probability that he makes exactly three of his next four free throws is
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4 (1/6) ^ 1 (5/6) ^ 3
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A college basketball player makes 80% of her free throws. Suppose this probability is the same for each free throw she attempts. The probability that she doesn't make a free throw until her fifth attempt this season is
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0.00128.
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The Binomial expression
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.2731
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A college basketball player makes 80% of her free throws. Suppose this probability is the same for each free throw she attempts. The expected number of free throws required until she makes her first free throw of the season is
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1.25
