This problem follows up on the previous two problems with the data in the Data2 sheet of the file. Here Niyaki did more investigation on the same 70 customers. It tracked subsequent failures and costs (if any) that occurred within the warranty period.
a. With these data, find the confidence intervals requested in the previous two problems.
b. Suppose that Niyaki sold this Blu-ray model to 12,450 customers during the year. Find a 95% confidence interval for its total net cost due to warranties from all of these sales.