Estimation of Population Mean and Standard deviation.
A production process is checked periodically by a value control inspector. The inspector selects simple random samples of 30 finished products and computes the sample mean product weights X If test results over's a long period of time show that 5 percent of the X values are over 2.1 pounds and 5 percent are under 1.9 pounds, what are the mean and standard deviations for the population of produced with this process?