Q: Which of the following is a correct formula for calculating the relative frequency of a class?

$$\text{Relative Frequency} = \frac{\text{Frequency of the class}}{\text{Total number of observations}}$$

Question 1

Which of the following best describes the main difference between a bar graph and a histogram?

Accepted Answer

A bar graph displays qualitative data, while a histogram displays quantitative data.

Question 2

Given the following frequency table for M&M colors: Brown (12), Yellow (10), Red (9), Orange (6), Blue (3), Green (5), what is the relative frequency of Red M&Ms? Use the formula $$	ext{relative frequency} = \frac{	ext{frequency}}{	ext{sum of all frequencies}}.$$

Accepted Answer

$$0.2$$

Question 3

A pie chart is constructed to represent the marital status of U.S. residents in 2006. If 58% are married, what is the central angle (in degrees) for the 'Married' sector? Use the formula $$	ext{angle} = 	ext{percentage} 	imes 360^\circ.$$

Accepted Answer

$$208.8^\circ$$

Question 4

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

Accepted Answer

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

Question 5

A histogram of the number of cars per household shows the highest bar at 2 cars. What is the shape of this distribution?

Accepted Answer

Skewed right

Question 6

If the smallest value in a data set is 672 and the largest is 738, and you want to create 7 classes for a frequency distribution, what is the appropriate class width? Use the formula $$	ext{class width} = \frac{	ext{largest value} - 	ext{smallest value}}{	ext{number of classes}}.$$

Accepted Answer

$$10$$

Question 7

Which of the following statements about stem-and-leaf plots is TRUE?

Accepted Answer

Stem-and-leaf plots retain the original data values, allowing the raw data to be retrieved.

Question 8

A time-series plot is most appropriate for which type of data?

Accepted Answer

Data collected at different points in time.

Question 9

Given the following cumulative frequency table for eruption times: 670–679 (2), 690–699 (9), 700–709 (18), 710–719 (27), 720–729 (38), 730–739 (45), what is the cumulative relative frequency for the class 710–719 if there are 45 total observations?

Accepted Answer

$$0.6$$

Question 10

Which of the following best describes a Pareto chart?

Accepted Answer

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

Question 11

If a dot plot is constructed for the number of cars in 50 households and the most dots are above the value 2, what does this indicate?

Accepted Answer

Most households have 2 cars.

Question 12

Which of the following is a correct formula for calculating the relative frequency of a class?

Accepted Answer

$$	ext{Relative Frequency} = \frac{	ext{Frequency of the class}}{	ext{Total number of observations}}$$

Question 13

A frequency polygon is constructed by plotting which of the following for each class?

Accepted Answer

The class midpoint and the frequency

Question 14

Which of the following distributions is described as having the highest frequency in the middle and frequencies that tail off to the left and right?

Accepted Answer

Bell-shaped distribution

Question 15

If a histogram for a data set shows a long tail to the right, how is the distribution described?

Accepted Answer

Skewed right

Question 16

Which of the following is a potential problem with using three-dimensional effects in statistical graphics?

Accepted Answer

They can distract the reader and lead to misinterpretation of the data.

Question 17

A cumulative frequency ogive is most useful for which of the following?

Accepted Answer

Determining the number of observations below a particular value.

Question 18

When constructing classes for a frequency distribution of continuous data, which of the following is TRUE?

Accepted Answer

The lower class limit of the first class is usually the smallest observation or a convenient number slightly lower.

Question 19

Which of the following is a real-world example where a time-series plot would be most appropriate?

Accepted Answer

Tracking the closing value of the Dow Jones Industrial Average from 1990 to 2007.

Question 20

Which of the following is a key advantage of a stem-and-leaf plot over a histogram?

Accepted Answer

It allows the original data values to be retrieved.

Organizing and Summarizing Data: Tables and Graphs in Statistics

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