A lathe is set to cut bars of steel into lengths of 9
centimeters. The lathe is considered to be in perfect adjustment if
the average length of the bars it cuts is 9 centimeters. A sample of
100 bars is selected randomly and measured. It is determined that
the average length of the bars in the sample is 9.085 centimeters.
Suppose the population standard deviation is 0.335 centimeters.
a. Formulate the hypotheses to determine whether or not the lathe is
in perfect adjustment. Please write out all steps used to solve.
b. Compute the test statistic. Please write out all steps used to solve.
c. Using the p-value approach, what is your conclusion? Let
α= 0.05. Please write out all steps used to solve.