Assume that 21 = 22 = 21. Calculate the pooled estimator of 2 for each of the

Question:

Assume that σ21 = σ22 = σ21. Calculate the pooled estimator of σ2 for each of the following cases:
a. s21 = 120, s22 = 100, n1 = n2 = 25
b. s2 = 12, s22 = 20, n1, = 20, n2 = 10
c. s2 = .15, s22 = .20, n1, = 6, n2= 10
d. s2 = 3,000, s22 = 2,500, n1 = 16, n2 = 17
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?