Q: Which formula is used to determine the class width when organizing continuous data into classes?

$$\text{Class width} = \frac{\text{largest data value} - \text{smallest data value}}{\text{number of classes}}$$

Question 1

Which of the following best describes a frequency distribution for qualitative data?

Accepted Answer

A table that lists each category of data and the number of occurrences for each category.

Question 2

A physical therapist records the body part requiring rehabilitation for 30 patients. Which of the following is the most appropriate first step to summarize this qualitative data?

Accepted Answer

Organize the data into a frequency distribution table.

Question 3

Given the following frequencies for body parts requiring rehabilitation: Back (12), Wrist (2), Elbow (1), Hip (2), Shoulder (4), Knee (5), Hand (1), Groin (1), Neck (1), what is the relative frequency for 'Shoulder'? Use the formula $$	ext{relative frequency} = \frac{	ext{frequency}}{	ext{sum of all frequencies}}.$$

Accepted Answer

$$\frac{4}{30} = 0.133$$

Question 4

Which type of graph is constructed by labeling each category of data on one axis and the frequency or relative frequency on the other, using rectangles of equal width?

Accepted Answer

Bar graph

Question 5

What distinguishes a Pareto chart from a standard bar graph?

Accepted Answer

Bars are arranged in decreasing order of frequency or relative frequency.

Question 6

Why should side-by-side bar graphs use relative frequencies instead of frequencies when comparing two data sets?

Accepted Answer

Because different sample or population sizes make comparisons using frequencies misleading.

Question 7

A pie chart is most appropriate for which of the following scenarios?

Accepted Answer

Displaying the proportion of students in different majors at a university.

Question 8

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

Accepted Answer

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

Question 9

If a bar graph starts its vertical axis at 30,000 instead of 0, what is the likely effect?

Accepted Answer

It may mislead readers to believe differences are larger than they actually are.

Question 10

Which of the following best describes the difference between a misleading and a deceptive graph?

Accepted Answer

A misleading graph unintentionally creates an incorrect impression, while a deceptive graph purposely creates an incorrect impression.

Question 11

A frequency distribution for the number of customers arriving at a restaurant in 40 intervals is constructed. What is the next step to visualize the data distribution?

Accepted Answer

Construct a histogram.

Question 12

Which formula is used to determine the class width when organizing continuous data into classes?

Accepted Answer

$$	ext{Class width} = \frac{	ext{largest data value} - 	ext{smallest data value}}{	ext{number of classes}}$$

Question 13

Which of the following is a key characteristic of a histogram?

Accepted Answer

Rectangles touch each other, representing classes of data.

Question 14

A distribution where the highest frequency occurs in the middle and frequencies tail off to the left and right is called:

Accepted Answer

Bell-shaped distribution

Question 15

Which type of graph is best for displaying how a variable changes over time?

Accepted Answer

Time-series plot

Question 16

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

Accepted Answer

Small sets of discrete quantitative data

Question 17

Which of the following is a potential pitfall when constructing a pie chart?

Accepted Answer

Exaggerating the size of a sector to mislead about the proportion of a category.

Question 18

If a histogram of parking fines in New York City is fairly symmetrical but not bell-shaped, how should the distribution be described?

Accepted Answer

Symmetrical but not bell-shaped

Question 19

Which of the following is NOT a recommended practice when constructing a graph?

Accepted Answer

Using more than one design in the same graphic to draw attention to specific areas.

Question 20

A researcher wants to compare the educational attainment of adults in 1990 and 2017. Which graphical method is most appropriate?

Accepted Answer

Side-by-side bar graph using relative frequencies

Chapter 2: Summarizing Data in Tables and Graphs

Study Guide - Practice Questions

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