In an automotive safety test conducted by the North Carolina Highway Safety Research Center, the average tire pressure in a sample of 62 tires was found to be 24 pounds per square inch, and the standard deviation was 2.1 pounds per square inch.
a) Calculate the estimated population standard deviation for this population. (There are about a million cars registered in North Carolina)
b) Calculate the estimated standard error of the mean.
c) Construct a 95 percent confidence interval for the population mean.