In the documentation that accompanies its products that are returned for in-warranty service, a manufacturer of electric can openers asks the customer to indicate the reason for the return. The codes and return problem categories are: (1) “doesn’t work,” (2) “excessive noise,” and (3) “other.” Data file XR09056 contains the problem codes for a simple random sample of 300 product returns. Based on this sample, construct and interpret the 95% confidence interval for the population proportion of returns that were because the product “doesn’t work.”
A computer and statistical software.