A textile fiber manufacturer is investigating a new drapery yarn, which the company claims has a mean thread elongation of 12 kilograms with a standard deviation of 0.5 kilograms. The company wishes to test the hypothesis H0: μ = 12 against H1: μ < 12, using a random sample of four specimens. (a) What is the type I error probability if the critical region is defined as x < 11.5 kilograms? (b) Find β for the case in which the true mean elongation is 11.25 kilograms. (c) Find β for the case in which the true mean is 11.5 kilograms.