# The amount of warpage in a type of wafer used in the manufacture of integrated circuits has mean 1.3 mm and standard deviation 0.1 mm. A random sample of 200 wafers is drawn. a) What is the probability that the sample mean warpage exceeds 1.305 mm? b) Find the 25th percentile of the sample mean. c) How many wafers must be sampled so that the probability is 0.05 that the sample mean exceeds 1.305?

Question

The amount of warpage in a type of wafer used in the manufacture of integrated circuits has mean 1.3 mm and standard deviation 0.1 mm. A random sample of 200 wafers is drawn. a) What is the probability that the sample mean warpage exceeds 1.305 mm? b) Find the 25th percentile of the sample mean. c) How many wafers must be sampled so that the probability is 0.05 that the sample mean exceeds 1.305?