16.20 Bootstrap t confidence interval for average delivery time by a robot. Return to or re-create the bootstrap distribution of the sample mean for the eight lunch delivery times in Exercise 16.11 (page 16-

11).

a. Although the sample is small, verify using graphs and numerical summaries of the bootstrap distribution that the distribution is reasonably Normal and that the bias is small relative to the observed x¯ .

b. The bootstrap t confidence interval for the population mean

μ is, therefore, justified. Give the 95% bootstrap t confidence interval for

μ .

c. Give the usual t 95% interval and compare it with your interval from part (b).