Question 11.23

11.23 Data analysis: Individual variables.

Table 11.3 gives data on the current fast-food market share, along with the number of franchises, number of company-owned stores, annual sales ($ million) from three years ago, and whether it is a burger restaurant.7 Market share is expressed in percents, based on current U.S. sales.

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  1. Make a table giving the mean, the standard deviation, and the five-number summary for each of these variables.
  2. Use stemplots or histograms to make graphical summaries of the five distributions.
  3. Describe the distributions. Are there any unusual observations?

11.23

(a)

Variable Mean Std Dev Minimum Lower Quartile Median Upper Quartile Maximum
Share 4.94 5.07 1.72 2.33 3.28 5.48 22.69
Franchises 5525.56 5754.47 0.00 1983.00 4406.50 6563.00 23850.00
Company 1116.31 1565.77 0.00 452.50 826.50 1194.50 6707.00
Sales 6.99 7.23 1.80 3.20 5.05 7.95 32.40
Burger 0.31 0.48 0.00 0.00 0.00 1.00 1.00

(c) McDonald’s is an outlier for Share and Sales, Subway is an outlier for Franchises, and Starbucks is an outlier for Company. Otherwise, it is hard to tell the distributions of the other restaurants because they are being squished on the histograms because of the outliers. Burger also only has two possible values.