Answer
Step 1 : $H_0$: µ = 34.9 months , $H_1$: µ $\neq$ 34.9 months
Step 2: Since α = 0.04, and the test is a double-tailed test, the critical value is -1.75 and +1.75.
Step 3:
$\bar{X}$ =28.5 months, µ =34.9 months, σ = 8.9 months, n = 40
Test value = z = $\frac{\bar{X}- µ }{σ / \sqrt n}$
= $\frac{28.5- 34.9}{8.9 / \sqrt 40}$
=-4.55
Step 4 : Since the test value falls beyond the critical value, the decision is to reject the null hypothesis.
Step 5: There is enough evidence to support the claim that the average stay has different with 34.9 months.
