Q: Suppose you have the following data for customer support call times (in minutes): 2, 5, 7, 8, 10, 12, 15. What is the estimated class width if you want to create 3 classes?

$$\text{Class width} = \frac{15 - 2}{3} = 4.33$$

Question 1

Which of the following best describes the difference between discrete and continuous data?

Accepted Answer

Discrete data are counted and typically represented by whole numbers, while continuous data are measured and can take on any value, including decimals.

Question 2

A frequency distribution is used to:

Accepted Answer

Graphically summarize information not readily observable by merely looking at data in a table.

Question 3

If you have a data set with 50 observations, what is the minimum number of classes $$k$$ you should use for a frequency distribution according to the $$2^k \geq n$$ rule?

Accepted Answer

$$k = 6$$

Question 4

Which of the following is NOT a recommended rule when constructing classes for grouped quantitative data?

Accepted Answer

Classes should be open-ended whenever possible.

Question 5

A cumulative relative frequency distribution shows:

Accepted Answer

The proportion of observations that are less than or equal to the class at which you are looking.

Question 6

Which Excel function is most appropriate for counting the number of occurrences of a specific category in qualitative data?

Accepted Answer

COUNTIF()

Question 7

What is the main purpose of a Pareto chart in business statistics?

Accepted Answer

To show the frequency of categories that cause quality control problems, arranged from most to least frequent.

Question 8

Suppose you have the following data for customer support call times (in minutes): 2, 5, 7, 8, 10, 12, 15. What is the estimated class width if you want to create 3 classes?

Accepted Answer

$$	ext{Class width} = \frac{15 - 2}{3} = 4.33$$

Question 9

Which type of chart is best for comparing the relative sizes of all possible categories in a data set?

Accepted Answer

Pie chart

Question 10

A stem and leaf display is most similar to which other graphical representation?

Accepted Answer

Histogram

Question 11

Which of the following consequences can result from using too many classes in a frequency distribution?

Accepted Answer

The histogram may become jagged and some classes may be empty.

Question 12

In a scatter plot, which variable is typically placed on the horizontal axis?

Accepted Answer

Independent variable

Question 13

Which of the following is a real-world example of continuous data?

Accepted Answer

Voltage of batteries produced in August

Question 14

What is the main advantage of a stem and leaf display over a histogram?

Accepted Answer

All original data points are visible in the display.

Question 15

Which of the following statements about bar charts is TRUE?

Accepted Answer

Bar charts are more useful than pie charts when you want to highlight actual data values and when the classes combined don’t form a whole.

Question 16

A contingency table is used to:

Accepted Answer

Display observations that have more than one value associated with them using rows and columns for separate variables.

Question 17

Which of the following is a correct step when constructing a histogram in Excel for grouped quantitative data?

Accepted Answer

Remove the gaps between bars to represent continuous data.

Question 18

If the cumulative relative frequency for the class '2 iPads sold per day' is 0.54, what does this mean?

Accepted Answer

54% of the days had two or fewer iPads sold.

Question 19

Which chart type is most appropriate for visualizing time series data?

Accepted Answer

Line chart

Question 20

A business analyst wants to compare the frequency of product returns by reason and also show the cumulative percentage of returns. Which chart should they use?

Accepted Answer

Pareto chart

Chapter 2: Displaying Descriptive Statistics – Business Statistics Study Notes

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