If the population is not normal but its standard deviation, σ is known and the sample size, n is large (n ≥ 30), z-distribution values may be used to determine interval estimates for the population mean.

Question

Quizplus · Accepted Answer

According to the Central Limit Theorem, when the sample size is large (n ≥ 30), the sampling distribution of the sample mean will be approximately normally distributed regardless of the shape of the population distribution. Therefore, z-distribution values can be used for interval estimates of the population mean when the population standard deviation is known, even if the population is not normally distributed.

If the Population Is Not Normal but Its Standard Deviation