9.87 Tennis balls in control? When it is operating correctly, a machine for manufacturing tennis balls produces balls with a mean weight of 57.6 grams. The last eight balls manufactured had weights 57.3, 57.4, 57.2, 57.5, 57.4, 57.1, 57.3, 57.0

a. Using a calculator or software, find the test statistic and P-value for a test of whether the process is in control against the alternative that the true mean of the process now differs from 57.6.

b. For a significance level of 0.05, explain what you would conclude. Express your conclusion so it would be understood by someone who never studied statistics.

c. If your decision in part b is in error, what type of error have you made?