Question 1

Which of the following best describes a frequency distribution?

Accepted Answer

A table that shows classes or intervals of data with a count of the number of entries in each class.

Question 2

Given the following classes: 10-14, 15-19, 20-24, what is the class width?

Accepted Answer

$$5$$

Question 3

If a data set has a minimum value of 22 and a maximum value of 97, and you want to create 8 classes, what is the class width?

Accepted Answer

$$\frac{97-22}{8} = 9.375$$, round up to $$10$$

Question 4

What is the formula for the midpoint of a class with lower class limit $$L$$ and upper class limit $$U$$?

Accepted Answer

$$\frac{L + U}{2}$$

Question 5

A frequency distribution has the following classes and frequencies: 1-5: 5, 6-10: 8, 11-15: 6. What is the cumulative frequency for the class 11-15?

Accepted Answer

$$5 + 8 + 6 = 19$$

Question 6

If a class has a frequency $$f = 7$$ and the sample size $$n = 30$$, what is the relative frequency of the class?

Accepted Answer

$$\frac{7}{30} \approx 0.23$$

Question 7

Why must consecutive bars in a frequency histogram touch?

Accepted Answer

To emphasize the continuous nature of the data.

Question 8

What is the purpose of class boundaries in a histogram?

Accepted Answer

To separate classes without forming gaps between them.

Question 9

Given a class with lower limit 50 and upper limit 59, and the next class starts at 60, what are the class boundaries?

Accepted Answer

Lower boundary: $$50 - 0.5 = 49.5$$, Upper boundary: $$59 + 0.5 = 59.5$$

Question 10

Which graph would you use to display the cumulative frequency of each class at its upper class boundary?

Accepted Answer

Ogive

Question 11

A data set of prescription expenses for 30 adults is grouped into 7 classes. If the most common range is $$299 to$$ $$334$$, what does this indicate about the data?

Accepted Answer

The mode of the grouped data is in the $$299 to$$ $$334$$ range.

Question 12

If you want to quickly see the proportion of data in each class, which graph should you use?

Accepted Answer

Relative frequency histogram

Question 13

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

Accepted Answer

Calculate the mean of each class.

Question 14

A frequency polygon is most useful for:

Accepted Answer

Emphasizing the continuous change in frequencies.

Question 15

If the cumulative frequency of the last class in a distribution is 50, what is the sample size?

Accepted Answer

$$50$$

Question 16

In a real-world scenario, why is it important to round up the class width to the next convenient number when constructing a frequency distribution?

Accepted Answer

To ensure that all data values are included and classes do not overlap.

Question 17

A hospital wants to analyze the distribution of patient ages. If the minimum age is 18 and the maximum is 92, and they want 10 classes, what is the class width?

Accepted Answer

$$\frac{92-18}{10} = 7.4$$, round up to $$8$$

Question 18

Which of the following statements about histograms is correct?

Accepted Answer

The vertical axis of a histogram represents the frequency of each class.

Descriptive Statistics: Frequency Distributions and Their Graphs

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