Multiple choice on Hypothesis testing, distributions

Please see the attached file for full problem description.

1. If standard deviation (sigma) is unknown when completing a hypothesis test about the population mean, then the best estimate for the unknown standard deviation is s. _____ T/F

2. The chi-square distribution is used for inferences about the population mean (mu) when the standard deviation (sigma) is unknown. ____ T/F

3. The t-distribution is used for all inferences about a population's variance. ___ T/F

4. When the means of two unrelated samples are used to compare two populations, we are dealing with two dependent means ___ T/F

5. Pretest versus post-test (before versus after) studies are usually independent samples. ____ T/F

6. The number of degrees of freedom for the critical value of t is equal to the smaller of n1 -1 or n2 -1 when making inferences about the difference between two independent means for the case when the degrees of freedom are estimated. ___ T/F

7. The F distribution is a symmetric distribution. ____ T/F

8. Which of the following would be the correct null hypotheses for testing the claim that the proportion of make students (M) who smoke at a particular college is greater than the proportion of female students (F) who smoke?
A. H0: pM (greater than or equal to) pF
B. H0: pM (less than or equal to) pF
C. H0: pM > pF
D. H0: pM < pF

9. Which of the following would be the correct hypotheses for testing the claim that the mean waiting time to be served at a large post office is at least 6.5 minutes?
A. H0: (mu) (greater than or equal to) 6.5 and Ha: (mu) < 6.5
B. H0: (mu) = 6.5 and Ha: (mu) (not equal to) 6.5
C. H0: (mu) (less than or equal to) 6.5 vs. Ha: (mu) > 6.5
D. H0: (mu) > 6.5 vs. Ha: (mu) (greater than or equal to) 6.5

10. The mean age of 25 randomly selected college seniors was found to be 23.5 years, and the standard deviation of all college seniors was 1.3 years. Which of the following is the correct symbol for 1.3 years?
A. (mu) B. s C. (sigma) D. X bar