Plastic bags used for packaging produce are manufactured so that the breaking strengths of the bags are normally distributed with a standard deviation of 1.8 pounds per square inch. A random sample of 16 bags is selected.
a. The probability is 0.01 that the sample standard deviation of breaking strengths exceeds what number?
b. The probability is 0.15 that the sample mean exceeds the population mean by how much?
c. The probability is 0.05 that the sample mean differs from the population mean by how much?