1) Suppose X follows uniform distribution with the range (2,5). Find the variance of X.

6/7

5/6

4/5

3/4

2)Choose one correct statement.

the central limit theorem shows the exact distribution of the sample mean.

the central limit theorem shows the approximate distribution is better than the exact distribution even when the exact distribution is known.

the central limit theorem shows the approximate distribution of the sample mean.

the central limit theorem shows the limit value of the sample mean as the sample size grows.