Suppose that four normal populations have means of 1 = 50, 2 = 60,

Suppose that four normal populations have means of µ₁ = 50, µ₂ = 60, µ₃ = 50, and µ₄ = 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 σ² = 25.