The Sampling Distribution of a Sample Mean

First, this section discusses the mean and variance of the sampling distribution of the mean. It also shows how central limit theorem can help to approximate the corresponding sampling distributions. Then, it talks about the properties of the sampling distribution for differences between means by giving the formulas of both mean and variance for the sampling distribution. Using the central limit theorem, it also talks about how to compute the probability of a difference between means being beyond a specified value.

Sampling Distribution of the Mean

Questions

Question 1 out of 5.
The population has a mean of 14 and a standard deviation of 3. The sample size of your sampling distribution is N=10. What is the mean of the sampling distribution of the mean?


Question 2 out of 5.
The population has a mean of 30 and a standard deviation of 6. The sample size of your sampling distribution is N=9. What is the variance of the sampling distribution of the mean?


Question 3 out of 5.
The population has a mean of 120 and a standard deviation of 12. The sample size of your sampling distribution is N=16. What is the standard error of the mean?


Question 4 out of 5.
The sampling distribution of the mean, with N=30, of a moderately negatively skewed distribution is:

Positively skewed

Negatively skewed

About normal


Question 5 out of 5.
The entire student body of 225 students took a test. These test scores have a mean of 75, a standard deviation of 10, and are slightly positively skewed. If you randomly chose 25 of these test scores and calculated the mean over and over again, what could be the mean, standard deviation, and skew of this distribution?

Mean = 75, SD = 10, Skew = 1.2

Mean = 75, SD = 0.67, Skew = 0.8

Mean = 80, SD = 2, Skew = -1.2

Mean = 75, SD = 2, Skew = about 0

Mean = 75, SD = 0.67, Skew = about 0