1.) You must use a t instead of a Z in your confidence interval formula for a mean when you don't know the value of sigma. (Assume you have a normal distribution.)

a) True

b) False

2.) A confidence interval is narrower if you use t than if you use Z. (Assume all else is the same.)

a) True

b) False

3.) The larger n is, the closer the t distribution looks to the Z distribution

a) True

b) False

4.) If you don't know the population standard deviation, what do you use as a substitute in your test statistic?

a) s

b) uo (stands for mu sub zero)

c) x-bar

d) sigma

5.) The t distribution is taller and thinner (more concentrated around the mean) than the Z distribution

a) True

b) False

6.) t_n-1 is a value on the t distribution with ______________________________ n-1

a) standard deviation

b) None of the other choices is correct

c) degrees of freedom

d) mean

7.) Suppose n = 10 and you want the value of t to put in your 95% confidence interval for the mean, where you don't know the population standard deviation. The value of t that you find on the t-table in this case is 2.2622

a) True

b) Fasle

8.) Suppose X has a normal distribution and you run a hypothesis test with Ho: u = 8 and Ha: u > 8. You collect a random sample of n = 11 values, and you find your test statistic is t = 2.50. What two values does the p-value lie between on the t-table?

a) None of the other choices is correct

b) .025< p value < .05

c.) .005 < p value < .01

d.) .01 < p value < .025

9.) Suppose X has a normal distribution and you run a hypothesis test with Ho: u = 8 and Ha: u > 8. You collect a random sample of n = 11 values, and you find your test statistic is t = 2.50. What is your decision?

a) Fail to Reject Ho

b) Reject Ho

10.) Suppose a 95% confidence interval for the mean is (10, 12) when you know the value of the population standard deviation (sigma). If you HAD NOT known the value of sigma, would your confidence interval have been wider, narrower, or the same?

a) wider

b) the same

c) No answer text provided.

d) narrower