Sample means based on at least _____ scores tend to approximate a normal distribution, even when the underlying population is skewed.
A) 10
B) 25
C) 30
D) 50

Question

Quizplus · Accepted Answer

According to the central limit theorem, sample means based on at least 30 scores tend to approximate a normal distribution, even when the underlying population is skewed. This is why choice C is the best option. While larger sample sizes can further improve the approximation to normality, 30 is generally considered to be a good benchmark for this purpose. Choice A and B are too small, while choice D is unnecessarily large.

Sample Means Based on at Least _____ Scores Tend to Approximate