Question 1

A frequency distribution is constructed for the number of hours college students spend studying per week. The minimum value is 2 hours and the maximum is 38 hours. If you want 6 classes, what is the appropriate class width?

Accepted Answer

$$\frac{38-2}{6} = 6 (so $$class width is 7 after rounding up)

Question 2

Which of the following best describes the lower class limit in a frequency distribution?

Accepted Answer

The smallest value that can belong to a class.

Question 3

Given the following class limits for a frequency distribution: 10-19, 20-29, 30-39, what is the class boundary between the first and second class?

Accepted Answer

$$19.5$$

Question 4

A data set of cholesterol levels (mg/dL) is grouped into classes with a class width of 25. If the first lower class limit is 150, what is the lower class limit of the fourth class?

Accepted Answer

$$150 + 3 	imes 25 = 225$$

Question 5

If a frequency distribution has the following frequencies for five classes: 2, 5, 8, 4, 1, what is the cumulative frequency for the fourth class?

Accepted Answer

$$2 + 5 + 8 + 4 = 19$$

Question 6

Which of the following statements about histograms is TRUE?

Accepted Answer

The bars in a histogram must touch because the data is continuous.

Question 7

A class in a frequency distribution has a lower class limit of 50 and an upper class limit of 59. What is the midpoint of this class?

Accepted Answer

$$\frac{50 + 59}{2} = 54.5$$

Question 8

In a study of daily water consumption, a class has a frequency of 12 and the total sample size is 60. What is the relative frequency of this class?

Accepted Answer

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

Question 9

Which of the following is NOT a correct step in constructing a frequency distribution?

Accepted Answer

Ensuring that classes overlap to include all data points.

Question 10

A frequency polygon is best described as:

Accepted Answer

A line graph that emphasizes the continuous change in frequencies.

Question 11

In a relative frequency histogram, what does the vertical axis represent?

Accepted Answer

The proportion or percentage of data in each class.

Question 12

Suppose you are constructing an ogive for a data set. What is plotted on the horizontal axis?

Accepted Answer

The upper class boundaries.

Question 13

A researcher is analyzing the number of hours people spend on social media per week. The data is grouped into classes: 0-4, 5-9, 10-14, 15-19. If the frequency for the 10-14 class is 18 and the total sample size is 60, what is the relative frequency for this class?

Accepted Answer

$$\frac{18}{60} = 0.3$$

Question 14

Which of the following best describes the cumulative frequency for a class in a frequency distribution?

Accepted Answer

The sum of the frequencies for that class and all previous classes.

Question 15

If the range of a data set is 48 and you want to create 8 classes, what is the minimum class width you should use?

Accepted Answer

$$\frac{48}{8} = 6 (so $$class width is 7 after rounding up)

Question 16

A frequency distribution for test scores has the following classes: 60-69, 70-79, 80-89, 90-99. What is the class width?

Accepted Answer

$$70 - 60 = 10$$

Question 17

Which of the following is a correct method for finding the midpoint of a class with lower class limit $$a$$ and upper class limit $$b$$?

Accepted Answer

$$\frac{a + b}{2}$$

Question 18

In a real-world scenario, a hospital records the number of patients admitted each day for a month. The data is grouped into classes with a class width of 5. If the first class is 0-4, what is the upper class limit of the third class?

Accepted Answer

$$4 + 2 	imes 5 = 14$$

Question 19

Which of the following graphs is most appropriate for displaying the cumulative frequency of a data set?

Accepted Answer

Ogive

Descriptive Statistics: Frequency Distributions and Their Graphs

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