EXAMPLE 17.1 Proportion of Tippers

CASE 17.1 In Chapter 8, we used sample proportions to estimate population proportions. For this study, 40 of the 69 male customers tipped a server who was wearing red and 130 of the 349 customers tipped a server who was wearing a different color. Our estimates of the two population proportions are

17-3

and

That is, we estimate that 58.0% of the male customers will tip if the server wears red, and 37.3% of the male customers will tip if the server wears a different color.