# Refer to Problem 3-26. (a) How would your answer change if a reasonable estimate of the experimental error variance were σ 2 = 36? (b) How would your answer change if a reasonable estimate of the experimental error variance were σ 2 = 49? (c) Can you draw any conclusions about the sensitivity of your answer in this particular situation

Refer to Problem 3-26.

(a) How would your answer change if a reasonable estimate of the experimental error variance were σ^{2} = 36?

(b) How would your answer change if a reasonable estimate of the experimental error variance were σ^{2} = 49?

(c) Can you draw any conclusions about the sensitivity of your answer in this particular situation about how your estimate of σ affects the decision about sample size?

(d) Can you make any recommendations about how we should use this general approach to choosing n in practice?

**Problem 3-26.**

Suppose that four normal populations have means of µ_{1} = 50, µ_{2} = 60, µ_{3} = 50, and µ_{4} = 60. How many observations should be taken from each population so that the probability of rejecting the null hypothesis of equal population means is at least 0.90? Assume that α = 0.05 and that a reasonable estimate of the error variance is σ^{2} = 25.

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