Suppose that shopping times for customers at a local grocery store are normally distributed with σ = 6 minutes. A
random sample of 16 shoppers in the local grocery store had a mean time of 25 minutes. Find 90%, 95%, and 99%
confidence intervals for the population mean, µ.

Question

Suppose that shopping times for customers at a local grocery store are normally distributed with σ = 6 minutes. A
random sample of 16 shoppers in the local grocery store had a mean time of 25 minutes. Find 90%, 95%, and 99%
confidence intervals for the population mean, µ.

b77w · Answer

I know the df = 15, meaning my t vals are +1.341 and -1.341