The 10 economic forecasters of a random sample were asked to forecast the rate of growth of the real gross national product (GNP) for the coming year. Suppose the probability distribution of the r.v.—forecast—is normal.
a. The probability is 0.10 that the sample variance of the forecast is more than X percent of the population variance. What is the value of X?
b. If the probability is 0.95 so that the sample variance is between X and Y percent of the population variance, what will be the values of X and Y?