Referring to Exercise 8.19, regard the sample of 15 alert times (which has standard deviation 1.026) as

Question:

Referring to Exercise 8.19, regard the sample of 15 alert times (which has standard deviation 1.026) as a preliminary sample. Determine the sample size needed to make us 95 percent confident that x-bar, the sample mean alert time, is within a margin of error of .3 second of μ, the population mean alert time using the new display panel.