Question 1

Which of the following best describes a relative frequency distribution?

Accepted Answer

A table that lists each category of data together with the proportion or percent of observations within each category.

Question 2

Given the formula for relative frequency $$ 	ext{Relative frequency} = \frac{	ext{frequency}}{	ext{sum of all frequencies}} $$, what is the relative frequency of a category with 12 observations in a dataset with 60 total observations?

Accepted Answer

$$ \frac{12}{60} = 0.2 $$

Question 3

Which type of graph is most appropriate for comparing the educational attainment of native- and foreign-born citizens, given different sample sizes?

Accepted Answer

A side-by-side bar graph using relative frequencies

Question 4

When constructing a histogram for continuous data, what does the width of each rectangle represent?

Accepted Answer

The class width (interval size)

Question 5

A dataset of unemployment rates by state is grouped into classes with lower class limits of 2.0, 3.0, 4.0, and 5.0. What is the class width?

Accepted Answer

$$ 1.0 $$

Question 6

Which of the following is NOT a possible shape for a distribution of quantitative data?

Accepted Answer

Categorical

Question 7

Refer to the time-series plot of age-adjusted death rates by ethnicity (see image 4). Which ethnicity experienced the greatest decrease in death rate from 2000 to 2017?

Accepted Answer

Non-Hispanic black

Question 8

Why might a pie chart be inappropriate for displaying the number of televisions owned by households?

Accepted Answer

Because there are too many categories, making the chart difficult to read

Question 9

A histogram is constructed for the number of siblings in a class. The histogram shows most students have 2 or 3 siblings, with fewer students having 0 or more than 5 siblings. What is the likely shape of this distribution?

Accepted Answer

Bell-shaped

Question 10

Which of the following is a common way that a graph can be misleading?

Accepted Answer

Using an inconsistent scale or a misplaced origin

Question 11

Suppose you are comparing the number of burglaries in Minneapolis during July-August and other months using a bar graph (see image 5). What could make this graph misleading?

Accepted Answer

The horizontal axis does not start at zero, exaggerating the difference

Question 12

Which of the following best describes a Pareto chart?

Accepted Answer

A bar graph with bars in decreasing order of frequency

Question 13

A dot plot is most useful for which type of data?

Accepted Answer

Small discrete datasets

Question 14

If a histogram has a long tail to the right, how is the distribution described?

Accepted Answer

Skewed right

Question 15

Which of the following is a key difference between a histogram and a bar graph?

Accepted Answer

Histograms have touching bars representing classes, bar graphs have separated bars for categories

Question 16

A frequency distribution for continuous data has the following classes: 10-19, 20-29, 30-39. What is the lower class limit of the second class?

Accepted Answer

$$ 20 $$

Question 17

Which of the following is a reason to use relative frequencies instead of frequencies when comparing two groups?

Accepted Answer

Relative frequencies allow comparison when sample sizes differ

Question 18

In the context of graphical misrepresentation, why is it problematic to use images of different sizes (such as in image 7) to represent percentages?

Accepted Answer

It can exaggerate differences due to area or volume effects

Question 19

A time-series plot is most useful for which of the following purposes?

Accepted Answer

Identifying trends in data over time

Question 20

If a dataset contains raw data, what is the first recommended step before analysis?

Accepted Answer

Organize the data into a frequency or relative frequency table

Chapter 2 STAT

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