1.) Suppose X has a normal distribution. If you do not know the population standard deviation and you want to estimate the mean of the population, what do you use?

a. Use the sample standard deviation.

b. Use the t-distribution c. Both a and b are correct.

2.) Suppose you want to make a confidence interval for the mean and X has a normal distribution, but you don't know the population standard deviation. What is the penalty you have to pay for using the SAMPLE standard deviation and not the POPULATION standard deviation? You use a t- value that is ____________ than Z, making the confidence interval ______________.

a. Bigger, wider b. Smaller, narrower

c. Bigger, narrower

d. Smaller, wider

3.) There is only one t-distribution and you use it for all different values of n.

a. True

b. False

4.) The t-distribution is flatter than the Z-distribution.

a. True

b. False

5.) For the same area you will have a/the __________________ t-value, compared to the Z-value.

a. Bigger

b. Smaller

c. Same

6.) The larger ___________is, the closer the t-distribution looks to the one and only Z-distribution.

a. n

b. p

c. s

d.

7.) To estimate the population mean when you don't know the population standard deviation, use the formula that contains t with ________________ degrees of freedom.

a. n b. n+1

c. n-1

d. 0

8.) Which value of t do you need on the t-table if you are doing a 95% confidence interval for the population mean, you don't know the population standard deviation, and n is 20?

a. 2.0860 b. 2.0796 c. 2.0930 d. None of these answers is correct.

9.) If you did a hypothesis test for the mean and you used a t-test instead of a test involving Z, and everything else remained the same, your pvalue for the t-test would be ____________ compared to the p-value for the test involving Z.

a. Smaller

b. The same

c. Larger

10.) Suppose you did a ONE TAILED t-test and the test statistic was 1.50, and the degrees of freedom for the test was 10 - 1 = 9, your p-value is between what two numbers, according to the t-table?

a. .1 and .05 b. .05 and .025 c. .15 and .10 d. None of these answers is correct.2