Paper Strength A manufacturer of paper used for packaging requires a minimum strength of 1400 glcm2
• To check on the quality of the paper, a random sample of 10 pieces of paper is selected each hour from the previous hour's production and a strength measurement is recorded for each. The standard deviation u of the strength measurements, computed by pooling the sum of squares of deviations of many samples, is known to equal 140 glcm?, and the strength measurements are normally distributed.
a. What is the approximate sampling distribution of the sample mean of n =10 test pieces of paper?
b. If the mean of the population of strength measurements is 1450 glcm2 , what is the approximate probability that, for a random sample of n =10 test pieces of paper, x-bar < 1400?
c. What value would you select for the mean paper strength mean( M) in order that P(x < 1400) be equal to 0.001?