Note on Homework 9

On the second part of the homework the statement reads

We have a sample of size n = 23, an average of x-bar = 87.6 and a standard deviation sx = 7.8.

The questions that follow ask for thresholds for 95% and 99% confidence both low and high. This is really asking you to look up numbers on Table A-3 on the salmon sheet, and you have more than enough information to do that with the statistics given.

Hint for smoker data set on salmon colored sheet

For the three data sets where you are trying to find x-bar and sx, here are the values of sigmax. If your calculator has a different value for sigmax, you need to check the data list to make sure you haven't made a mistake. The size of each of the data sets is n = 40. Round your answers to two places after the decimal.

Smokers: sigmax = 117.9951244
Exposed non-smokers: sigmax = 136.3469632
Non-exposed non-smokers: sigmax = 61.74688251