Question 8.61

8.61 To tip or not to tip

A study of tipping behaviors examined the relationship between the color of the shirt worn by the server and whether or not the customer left a tip.15 There were 418 male customers in the study; 40 of the 69 who were served by a server wearing a red shirt left a tip. Of the 349 who were served by a server wearing a different colored shirt, 130 left a tip.

  1. What is the explanatory variable for this setting? Explain your answer.
  2. What is the response variable for this setting? Explain your answer.
  3. What are the parameters for this study? Explain your answer.

8.61

(a) The explanatory variable is the color of the shirt; it is used to explain whether or not a tip was given. (b) The response variable is whether a tip was given or not; it is the interest of the study. (c) is the true proportion of male customers who would leave a tip for a red-shirt server. is the true proportion of male customers who would leave a tip for a different-colored-shirt server.