4. Suppose that five normal populations have common variance sigma ^2 = 100 and means µ1 = 175, µ2 = 190, µ3 = 160, µ4 = 200, µ5 = 215. a) How many observations per population must be taken so that the probability of rejecting the hypothesis of equality of means is at least 0.95? Use alpha = 0.05.