6. It is the value on the t distribution whose left tail probability is 93% and whose right-tail probability is 7%.

A. left t-value

B. 7th percentile

C. right t-value

D. 93rd percentile

7. When do you use t-distribution instead of normal distribution? *

A. If the population standard deviation is known

B. If the sample standard deviation is unknown

C. When the sample size is less than 30.

D. When the sample size is greater than or equal to 30

8. For a 95% confidence level, the confidence coefficient is ____? *

A. 2.58

B. 1.96

C. 2.33

D. 1.645

9. In Student's t-distribution, if the sample size is 25, what is the degree of freedom? *

A. 24

B. 26

C. 5

D. 25

10. What is the 95th percentile of the t-distribution if the sample size is 15? *

A. 1.771

B. 1.345

C. 1.753

D. 1.761