# Question: Assume that 12 22 2 Calculate the pooled

Assume that σ12 = σ22 = σ2. Calculate the pooled estimator of σ2 for each of the following cases:

a. s12 = 200, s22 = 180, n1 = n2 = 25

b. s12 = 25, s22 = 40, n1 = 20, n2 = 10

c. s12 = .20, s22 = .30, n1 = 8, n2 = 12

d. s12 = 2,500, s22 = 1,800, n1 = 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 cases a–d?

a. s12 = 200, s22 = 180, n1 = n2 = 25

b. s12 = 25, s22 = 40, n1 = 20, n2 = 10

c. s12 = .20, s22 = .30, n1 = 8, n2 = 12

d. s12 = 2,500, s22 = 1,800, n1 = 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 cases a–d?

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