The mean breaking strength of yarn employed in manufacturing drapery material is needed to be at least 100 psi. Past experience has indicated that the standard deviation of breaking strength is 2 psi. A random sample of nine specimens is tested, and the average breaking strength is found to be 100.6 psi.
a. Should the fiber be judged acceptable? Use the P-value approach.
b. What is the probability of not rejecting the null hypothesis at a=0.05 if the fiber has a true mean breaking strength of 102 psi?
c. Find a 95% one-sided lower CI on the true mean breaking strength.