Refer to Exercise 21.

Use the more accurate normal approximation to estimate the critical values X2 0.025 and X2 0.975. Using these critical values, can you reject H0 at the

α = 0.05 level?

A more accurate normal approximation to X2α is given by

where z???? is the z-score that has area α to its right.

Exercise 21

A sample of size 101 from a normal population has sample standard deviation s = 40.

Use Table A.4 to find the exact critical values X2 0.025 and X2 0.975 to test H0: σ = 30 versus H1: σ ≠ 30.

Can you reject H0 at the α = 0.05 level?

2 2 0.5 (za + 2k - 1