s 2 = 36,000,000 and df = 18. From Table 14.3, the intersection of the 0.025 column with 18 df is 31.53 for the right tail and 8.23 for the left tail.

Substitution in Eq. (14.8) yields P[20,551,855 < cr 2 < 78,736,330] = 0.95, and taking square roots yields P[4533 < cr < 8873] = 0.95. Because cr for a healthy population would be about 1200-1300, the variability does indeed appear to be abnormally large.