16.) Suppose X has a normal distribution with mean 15 and standard deviation 5. What is the probability that X is between 10 and 12? Choose the closest answer.

a) 0.35

b) 0.15

c) 0.55

d) 0.25

17.) Which of the following statements is false?

a) Statement 2: The t-distribution is flatter and fatter than the Z-distribution.

b) None of the 3 statements are false.

c) Statement 1: The t-distribution has a smaller standard deviation than the Z-distribution.

d) All of the 3 statements are false.

e) Statement 3: The larger n is, the closer the t-distribution gets to the Z distribution.

18.) Which of the following statements is false?

a) All of the 3 statements are false.

b)Statement 1: The standard error of X-bar is equal to the standard deviation of X

c) None of the 3 statements are false.

d) Statement 3: If X-has a normal distribution, X-bar is normal only if n > 30.

e) Statement 2: Suppose X has a non-normal distribution, Then X-bar has a normal distribution for any n by the CLT.

19.) Suppose you surveyed 1000 randomly chosen people from your population and you found that 15% of them collect stamps. You want to estimate the proportion of people who collect stamps using your data. What is the margin of error? Choose the closest answer.

a) 0.03

b) Not enough information to tell

c) 0.01

d) 0.05

e) 0.02

20.) Suppose X has the following probability distribution. Find the mean of 2X - 1

X	2	3	4
p(x)	0.5	0.3	0.2

a) None of the other choices is correct

b) 2,7

c) 4.4

d) 5.4