With reference to Example 13.8, show that the critical region is x ≤ 5 or x ≥ 15 and that, corresponding to this critical region, the level of significance is actually 0.0414.
Example 13.8
If x = 4 of n = 20 patients suffered serious side effects from a new medication, test the null hypothesis θ = 0.50 against the alternative hypothesis θ ≠ 0.50 at the 0.05 level of significance. Here θ is the true proportion of patients suffering serious side effects from the new medication.