The Wilson Company uses a great deal of water in the process of making industrial milling equipment. To determine whether the company is complying with federal clean water laws, sample measures are taken every so often. One requirement is that the median pH level must be lower than 7.4. A sample of 95 pH measures has been taken. The data for these measures are in the file Wilson Water.

a. Carefully examine the data. Use an appropriate procedure to determine if the data could have been sampled from a normal distribution. (Hint: Review the goodness-of-fit test in Chapter 13.)

b. Based on the sample data of pH level, what should the company conclude about its current status on meeting federal requirements? Test the hypothesis at the 0.05 level.