If the sample sizes are greater than 30 and the population variances are known, the basis for statistical inferences about the difference in two population means using two independent random samples is the z-statistic, regardless of the shapes of the population distributions.

Question

Quizplus · Accepted Answer

When sample sizes are greater than 30, the Central Limit Theorem suggests that the sampling distribution of the sample mean will be approximately normally distributed regardless of the shape of the population distribution. If the population variances are known, the z-statistic is used for inference about the difference between two population means.

If the Sample Sizes Are Greater Than 30 and the Population