Question 1

A physical therapist records the body part requiring rehabilitation for 30 patients. The frequency distribution shows that 'Back' appears 12 times. What is the relative frequency of 'Back' injuries in this sample?

Accepted Answer

$$\frac{12}{30} = 0.4$$

Question 2

Which of the following best describes a Pareto chart?

Accepted Answer

A bar graph in which bars are drawn in decreasing order of frequency or relative frequency.

Question 3

Why is it preferable to use relative frequencies rather than frequencies when comparing two data sets of different sizes?

Accepted Answer

Relative frequencies account for differences in sample or population sizes, making comparisons more meaningful.

Question 4

Which type of graph is best for comparing one category to the whole?

Accepted Answer

Pie chart

Question 5

Given the following frequency distribution for educational attainment, what is the relative frequency of 'Bachelor’s degree' holders? (Total = 224,580; Bachelor’s degree = 52,805)

Accepted Answer

$$\frac{52,805}{224,580} \approx 0.235$$

Question 6

Which of the following is NOT a guideline for constructing a good graph?

Accepted Answer

Use three-dimensional effects to make the graph more visually appealing.

Question 7

A histogram is constructed for a data set. What happens to the number of classes as the bin width increases?

Accepted Answer

The number of classes decreases.

Question 8

Which of the following best describes a bell-shaped distribution?

Accepted Answer

The highest frequency occurs in the middle and frequencies tail off to the left and right.

Question 9

What is the main advantage of a stem-and-leaf plot over a histogram?

Accepted Answer

The raw data can be retrieved from the stem-and-leaf plot.

Question 10

A cumulative frequency distribution is constructed for a data set. How do you find the cumulative frequency for the fifth class?

Accepted Answer

Add the frequencies of the first five classes.

Question 11

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

Accepted Answer

Using inconsistent scales on the axes.

Question 12

When is it preferable to use horizontal bars rather than vertical bars in a bar graph?

Accepted Answer

When category names are lengthy.

Question 13

Which of the following best describes a time-series graph?

Accepted Answer

A graph that plots time on the horizontal axis and the variable of interest on the vertical axis, connecting points with line segments.

Question 14

What is the formula for calculating the class width when organizing continuous data into a frequency distribution?

Accepted Answer

$$	ext{Class width} = \frac{	ext{Largest data value} - 	ext{Smallest data value}}{	ext{Number of classes}}$$

Question 15

Which of the following is true about the sum of relative frequencies in a relative frequency distribution?

Accepted Answer

It should be equal to 1, but may differ slightly due to rounding.

Question 16

Which of the following is a scenario where a stem-and-leaf plot loses its usefulness?

Accepted Answer

When the data set is large or has a large range of values.

Question 17

A distribution is described as 'skewed right.' Which of the following best describes its shape?

Accepted Answer

The tail to the right of the peak is longer than to the left.

Question 18

Which of the following is a key step in constructing a frequency polygon?

Accepted Answer

Plot a point above each class midpoint at a height equal to the class frequency and connect the points with line segments.

Question 19

Which of the following is NOT a common misrepresentation of data in graphs?

Accepted Answer

Using consistent increments between tick marks.

Organizing and Summarizing Data: Qualitative and Quantitative Displays

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