Assume that a: = a; = u2. Calculate the pooled estimator of a2 for each of the following cases:

a. s: = 120, s; = 100, n, = n2 = 25

b. s: = 12, s; = 20, n1 = 20, n, = 10

c. s: = .15, s; = .20, n, = 6, n, = 10

d. s: = 3,000, s; = 2,500, n, = 16, n2 = 17

e. Note that the pooled estimate is a weighted average of the sample variances. To which of the variances does the pooled estimate fall nearer in each of the above cases?