The z-distribution is used to estimate a population mean for large samples if the population standard deviation is known."Large" is usually defined as _______.
A)at least 10
B)at least 5% of the population size
C)at least 30
D)at least 12
E)at least 100

Question

Quizplus · Accepted Answer

The threshold for considering a sample as "large" for the purposes of using the z-distribution is typically at least 30. This is based on the Central Limit Theorem, which suggests that the sampling distribution of the sample mean will be approximately normally distributed if the sample size is large enough, usually 30 or more, regardless of the shape of the population distribution.

The Z-Distribution Is Used to Estimate a Population Mean for Large