# Chapter 2 Homework

As part of the marketing group at a film​ studio, you are asked to find out the age distribution of the audience of the​ studio’s latest family friendly film. With the help of 10 of your​ colleagues, you conduct exit interviews by randomly selecting people to question at 20 different movie theatres. From 474474 ​responses, you find out that 4343 are younger than​ 6, 8787 are 6 to 9 years​ old, 152152 are 10 to​ 14, 1717 are 15 to​ 21, and 175175 are older than 21.

List frequencies of each age group in order.

43, 87, 152, 17, 175
As part of the marketing group at a film​ studio, you are asked to find out the age distribution of the audience of the​ studio’s latest family friendly film. With the help of 10 of your​ colleagues, you conduct exit interviews by randomly selecting people to question at 20 different movie theatres. From 474474 ​responses, you find out that 4343 are younger than​ 6, 8787 are 6 to 9 years​ old, 152152 are 10 to​ 14, 1717 are 15 to​ 21, and 175175 are older than 21.

Find relative frequency (%) of each age group in order.

9.07%, 18.35%, 32.07%, 3.59%, 36.92%
The human resource group for a company collected data summarizing the educational levels and tenures of the​ company’s employees. The different educational levels are no college degree​ (None), associate’s degree​ (AA), bachelor’s degree​ (BA), master’s degree​ (MA), and PhD. The three levels of tenure are less than 1​ year, between 1 and 5​ years, and more than 5 years.

Find the marginal distribution of the tenure in order of length.

98, 202, 198
The human resource group for a company collected data summarizing the educational levels and tenures of the​ company’s employees. The different educational levels are no college degree​ (None), associate’s degree​ (AA), bachelor’s degree​ (BA), master’s degree​ (MA), and PhD. The three levels of tenure are less than 1​ year, between 1 and 5​ years, and more than 5 years.

Find the marginal distribution of education level in order of length.

156, 39, 211, 60, 32
The pie chart summarizes the genres of 125125 ​first-run movies released one year.
A pie chart contains four sectors.

Is this an appropriate display for the genres, why?

Yes, because each movie falls into only one category and no categories overlap.
The pie chart summarizes the genres of 125125 ​first-run movies released one year.
A pie chart contains four sectors.

Which genre is least common?

Drama; stalled section and listed at bottom of descending order
An article reported the national market share of leading sellers of carbonated soft drinks. The pie chart and bar chart below display the values.

Which is better for displaying the relative portions of market share, why?

The pie chart because it shows the categories as portions of a whole
An article reported the national market share of leading sellers of carbonated soft drinks. The pie chart and bar chart below display the values.

Is anything missing from the displays?

No
An agency recently surveyed people from different​ countries, asking them​ “How important is acquiring wealth to​ you?” The percent who responded that it was more than average importance​ were: 70.370.3​% country​ A, 58.358.3​% country​ B, 76.976.9​% country​ C, 44.844.8​% country​ D, and 44.544.5​% country E. There were about 1500 respondents per country. A report showed the accompanying bar chart of these percentages.

How much larger is the proportion of those who said acquiring wealth was more important in country C than in country E?

32.4%
An agency recently surveyed people from different​ countries, asking them​ “How important is acquiring wealth to​ you?” The percent who responded that it was more than average importance​ were: 70.370.3​% country​ A, 58.358.3​% country​ B, 76.976.9​% country​ C, 44.844.8​% country​ D, and 44.544.5​% country E. There were about 1500 respondents per country. A report showed the accompanying bar chart of these percentages.

Is this impression given by the display?

No, country C’s percentage is about 6 times as big, but in reality not even twice as big
An agency recently surveyed people from different​ countries, asking them​ “How important is acquiring wealth to​ you?” The percent who responded that it was more than average importance​ were: 70.370.3​% country​ A, 58.358.3​% country​ B, 76.976.9​% country​ C, 44.844.8​% country​ D, and 44.544.5​% country E. There were about 1500 respondents per country. A report showed the accompanying bar chart of these percentages.

How could the display be improved?

Start the percentages at 0% on the vertical axis, not 40%
An agency recently surveyed people from different​ countries, asking them​ “How important is acquiring wealth to​ you?” The percent who responded that it was more than average importance​ were: 70.370.3​% country​ A, 58.358.3​% country​ B, 76.976.9​% country​ C, 44.844.8​% country​ D, and 44.544.5​% country E. There were about 1500 respondents per country. A report showed the accompanying bar chart of these percentages.

Describe the information the graph has presented.

The percentage of people who say that wealth is important to them is highest i countries A and C (around 75%), followed by country B (around 60%), and then countries D and E, where the percentage is only about 45%
A company held a blood pressure screening clinic for its employees. The results are summarized in the table below by age group and blood pressure level.

Find the marginal distribution of blood pressure:

20%, 49.4%, 30.6% (equal 100)
A company held a blood pressure screening clinic for its employees. The results are summarized in the table below by age group and blood pressure level.

Find the conditional distribution of blood pressure level within each age group.

29.7%, 45.5%, 24.8%
20%, 52.6%, 27.4%
14.9%, 48.5%, 36.6%
A company held a blood pressure screening clinic for its employees. The results are summarized in the table below by age group and blood pressure level.

Briefly describe the association between age and blood pressure among these employees.

The percentage of employees having low blood pressure decreases and the percentage having high blood pressure increases as they age
A company held a blood pressure screening clinic for its employees. The results are summarized in the table below by age group and blood pressure level.

Does this prove that people’s blood pressure levels increase as they age, explain.

No, because only a controlled experiment can isolate the relationship between age and blood pressure