Q: Given the following class limits for a frequency distribution: 10-19, 20-29, 30-39, what is the class width?

$$\text{Class width} = \text{Lower limit of second class} - \text{Lower limit of first class} = 20 - 10 = 10$$

Q: In a frequency distribution, what is the formula for relative frequency?

$$\text{Relative frequency} = \dfrac{\text{Frequency of the class}}{\text{Total number of data entries}}$$

Question 1

Which of the following best describes a frequency distribution?

Accepted Answer

A table that shows the number of data entries in each class or interval.

Question 2

Given the following class limits for a frequency distribution: 10-19, 20-29, 30-39, what is the class width?

Accepted Answer

$$	ext{Class width} = 	ext{Lower limit of second class} - 	ext{Lower limit of first class} = 20 - 10 = 10$$

Question 3

A data set has the following values: 2, 4, 4, 5, 7, 8, 8, 8, 10. What is the mode?

Accepted Answer

8

Question 4

Which of the following is a disadvantage of using the mean as a measure of central tendency?

Accepted Answer

It can be greatly affected by outliers.

Question 5

A stem-and-leaf plot is most useful for which of the following purposes?

Accepted Answer

Sorting and displaying small to moderate quantitative data sets while retaining original values.

Question 6

Given the following frequency distribution, what is the cumulative frequency for the third class?

Class: 10-19 (f=2), 20-29 (f=5), 30-39 (f=8), 40-49 (f=3)

Accepted Answer

$$2 + 5 + 8 = 15$$

Question 7

A pie chart is best used for which type of data?

Accepted Answer

Qualitative data

Question 8

Which of the following statements about a Pareto chart is correct?

Accepted Answer

It is a bar graph with bars positioned in order of decreasing height, used for qualitative data.

Question 9

A data set has the following values: 3, 5, 7, 9, 100. Which measure of central tendency is most affected by the outlier 100?

Accepted Answer

Mean

Question 10

In a frequency distribution, what is the formula for relative frequency?

Accepted Answer

$$	ext{Relative frequency} = \dfrac{	ext{Frequency of the class}}{	ext{Total number of data entries}}$$

Question 11

A histogram is constructed for a set of exam scores. Which of the following is NOT a correct property of a histogram?

Accepted Answer

The bars are always arranged in order of decreasing height.

Question 12

Given the following data set: 12, 15, 18, 21, 24, what is the sample mean?

Accepted Answer

$$\bar{x} = \dfrac{12 + 15 + 18 + 21 + 24}{5} = \dfrac{90}{5} = 18$$

Question 13

A dot plot is best suited for which of the following scenarios?

Accepted Answer

Displaying the distribution of a small set of discrete quantitative data.

Question 14

A time series graph is used to:

Accepted Answer

Show how a quantitative variable changes over regular intervals of time.

Question 15

If a frequency polygon is constructed from a frequency distribution, what is plotted on the x-axis?

Accepted Answer

Class midpoints

Question 16

A scatter plot is used to:

Accepted Answer

Display the relationship between two quantitative variables.

Question 17

Given the following data set: 5, 7, 8, 12, 15, what is the median?

Accepted Answer

8

Question 18

Which of the following is true about class boundaries in a frequency distribution?

Accepted Answer

They are found by averaging the upper class limit of one class and the lower class limit of the next.

Question 19

A misleading graph is one that:

Accepted Answer

Uses a non-zero baseline to exaggerate differences.

Question 20

A sample of 10 students has the following test scores: 60, 62, 65, 68, 70, 72, 75, 78, 80, 100. Which measure of central tendency best represents the center of the data set?

Accepted Answer

Median, because it is less affected by the outlier 100.

Descriptive Statistics: Frequency Distributions, Graphs, and Measures of Central Tendency

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