Which of the following conditions must be met if you want to use z-procedures to construct a confidence interval for a population proportion?

a. the sample size must be at least 30 (some texts say 50).
b the population must be at least 10 times as large as the sample (some texts say 20).
c. both npˆ and n(1 − pˆ) must be at least 10 (some texts say greater than 5).

A. The sample size must be at least 30 (some texts say 50).

Step-by-step explanation:

The Central Limit Theorem estabilishes that, for a random variable X, with mean and standard deviation , a large sample size, of at least 30, can be approximated to a normal distribution with mean and standard deviation .

So the correct answer is:

A. The sample size must be at least 30 (some texts say 50).

step-by-step explanation: