# Question

Independent random samples from two normally distributed populations give the following results:

nx = 10 x-bar = 480 sx = 30

ny = 12 y-bar = 520 sy = 25

a. If we assume that the unknown population variances are equal, find the 90% confidence interval for the difference of population means.

b. If we do not assume that the unknown population variances are equal, find the 90% confidence interval for the difference between population means.

nx = 10 x-bar = 480 sx = 30

ny = 12 y-bar = 520 sy = 25

a. If we assume that the unknown population variances are equal, find the 90% confidence interval for the difference of population means.

b. If we do not assume that the unknown population variances are equal, find the 90% confidence interval for the difference between population means.

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