Refer to Exercise 7.37 and the weights of tees produced by an injection mold process. If operating correctly, the process will produce tees with a weight variance of .000004 1ounces22. If the weight variance differs from .000004, the injection molder is out of control.

a. Set up the null and alternative hypotheses for testing whether the injection mold process is out of control.

b. Use the data saved in the accompanying file to conduct the test, part a. Use α = .01.

c. What conditions are required for inferences derived from the test to be valid? Are they reasonably satisfied?