Business Analytics

Practice 1 Questions

Descriptive Statistics and Data Visualization

1

CHAPTER 2

14. Consider a sample with data values of 27, 25, 20, 15, 30, 34, 28, and 25. Compute the 20th,

25th, 65th, and 75th percentiles.

15. Consider a sample with data values of 53, 55, 70, 58, 64, 57, 53, 69, 57, 68, and 53. Compute the mean, median, and mode.

18. The average time that Americans commute to work is 27.7 minutes (Sterling’s Best Places, April 13, 2012). The average commute times in minutes for 48 cities are as follows [Data File:

CommuteTimes]:

Practice 1 Questions

Descriptive Statistics and Data Visualization

2

a. What is the mean commute time for these 48 cities? b. What is the median commute time for these 48 cities?

c. What is the mode for these 48 cities?

d. What is the variance and standard deviation of commute times for these 48 cities? e. What is the third quartile of commute times for these 48 cities?

24. Five observations taken for two variables follow.

a) Develop a scatter diagram with x on the horizontal axis. b) What does the scatter diagram developed in part a indicate about the relationship between

the two variables?

c) Compute and interpret the sample covariance. d) Compute and interpret the sample correlation coefficient.

Practice 1 Questions

Descriptive Statistics and Data Visualization

3

CHAPTER 3

3) The following table provides monthly revenue values for Tedstar, Inc., a company that sells valves to large

industrial firms. The monthly revenue data have been graphed using a line chart in the following

figure. (Data File: Tedstar)

a. What are the problems with the layout and display of this line chart? b. Create a new line chart for the monthly revenue data at Tedstar, Inc. Format the chart to make it easy

to read and interpret

6. The file MutualFunds contains a data set with information for 45 mutual funds that are part of the

Morningstar Funds 500. The data set includes the following five variables:

 Fund Type: The type of fund, labeled DE (Domestic Equity), IE (International Equity), and FI (Fixed Income)

 Net Asset Value ($): The closing price per share

 Five-Year Average Return (%): The average annual return for the fund over the past five years

 Expense Ratio (%): The percentage of assets deducted each fiscal year for fund expenses

 Morningstar Rank: The risk adjusted star rating for each fund; Morningstar ranks go from a low of 1 Star to a high of 5 Stars.

a. Prepare a PivotTable that gives the frequency count of the data by Fund Type (rows) and the five -year

average annual return (columns). Use classes of 0–9.99, 10–19.99, 20–29.99, 30–39.99, 40–49.99, and

50–59.99 for the Five-Year Average Return (%).

Practice 1 Questions

Descriptive Statistics and Data Visualization

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b. What conclusions can you draw about the fund type and the average return over the past five years?

9) The following 20 observations are for two quantitative variables, x and y. (Data File: Scatter)

a. Create a scatter chart for these 20 observations.

b. Fit a linear trendline to the 20 observations. What can you say about the relationship between the two

quantitative variables?

13. The following table contains sales totals for the top six term life insurance salespeople at American

Insurance.

a. Create a column chart to display the information in the table above. Format the column chart to best display

the data by adding axes labels, a chart title, etc.

b. Sort the values in Excel so that the column chart is ordered from most contracts sold to fewest.

c. Insert data labels to display the number of contracts sold for each salesperson above the columns in the

column chart created in part a.

Practice 1 Questions

Descriptive Statistics and Data Visualization

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14. The total number of term life insurance contracts sold in Problem 13 is 199. The following pie chart shows

the percentages of contracts sold by each salesperson.

a. What are the problems with using a pie chart to display these data?

b. What type of chart would be preferred for displaying the data in this pie chart?

c. Use a different type of chart to display the percentage of contracts sold by each salesperson that conveys the

data better than the pie chart. Format the chart and add data labels to improve the chart’s readability.

17. The Northwest regional manager of Logan Outdoor Equipment Company has conducted a study to

determine how her store managers are allocating their time. A study was undertaken over three

weeks that collected the following data related to the percentage of time each store manager spent on

the tasks of attending required meetings, preparing business reports, customer interaction, and being

idle. The results of the data collection appear in the following table. [Data File: Logan]

Practice 1 Questions

Descriptive Statistics and Data Visualization

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a. Create a stacked-bar chart with locations along the vertical axis. Reformat the bar chart to best display these

data by adding axis labels, a chart title, and so on.

b. Create a clustered-bar chart with locations along the vertical axis and clusters of tasks. Reformat the bar

chart to best display these data by adding axis labels, a chart title, and the like.

c. Create multiple bar charts in which each location becomes a single bar chart showing the percentage of time

spent on tasks. Reformat the bar charts to best display these data by adding axis labels, a chart title,

and so forth.

d. Which form of bar chart (stacked, clustered, or multiple) is preferable for these data? Why?

e. What can we infer about the differences among how store managers are allocating their time at the different

locations?