Question

Computer Depot is a large store that sells and repairs computers. A random sample of 110 computer repair jobs took technicians an average of 93.2 minutes per computer. Assume that o is known to be 16.9 minutes. Find a 99% confidence interval for the population mean u for the computer repairs. Interpret the interval in the context of this problem. State what assumptions were met to use the method you selected.

Answer 1

For raw score, use SD, but for means, use Standard Error of the mean (SEm).

99% = mean ± 2.585 SEm

SEm = SD/√n

Answer 2

678 to 56.8