Answer:
a. The sample has more than 30 grade-point averages.
Step-by-step explanation:
Given that a researcher collects a simple random sample of grade-point averages of statistics students, and she calculates the mean of this sample
We are asked to find the conditions under which that sample mean can be treated as a value from a population having a normal distribution
Recall central limit theorem here
The central limit theorem states that the mean of all sample means will follow a normal distribution irrespective of the original distribution to which the data belonged to provided that
i) the samples are drawn at random
ii) The sample size should be atleast 30
Hence here we find that the correct conditions is a.
Only option a is right
a. The sample has more than 30 grade-point averages.
