1. Explain the difference between testing a single mean and testing the difference between two means.
2. What is the main difference between dependent and Independent samples? (Give examples)
3. What is the purpose of two samples "t" test?
4. How is the chi-square independence test similar to the goodness-of-fit test? How is it different?
5. What is the difference between McMemar's Test and the Chi-squared test for 2 by 2 table.
6. A clinic administers two drugs to two groups of randomly assigned patients to cure the same disease: 70 patients received Drug 1 and 80 patients received Drug 2. The following table gives the information about the number of patients cured and the once not cured by each of these two drugs

	Cured	Not cured
Drug 1	59	11
Drug 2	61	19

A. For this contingency table, what is the number of degrees of freedom? (Show calculations)

1. 4
2. 3
3. 1
4. 2

B.For this contingency table, what are the observed frequencies for the first row? (Show calculations)

1. 56 and 14
2. 59 and 11
3. 59 and 61
4. 56 and 64

C. For this contingency table, what are the expected frequencies for the first row? (Show calculations)

1. 59 and 11
2. 59 and 61
3. 56 and 64
4. 56 and 14

D. For this contingency table, what is the critical value of chi square, use 10% significance level? (Show Calculations)

1. 5.991
2. 4.605
3. 3.841
4. 2.706

E. What is the test statistics for this contingency table? (Show calculations)

1. 1.51
2. 2.15
3. 1.61
4. 2.15

F.Based on chi-squared test, we can say that

1. The drug is effective
2. The drug is not effective

For this question, please answer in the following format:

A	B	C	D	E	F

7. What is the difference between the independent variable and the dependent variable? Give examples

8. Give two examples in any area of interest to you where regression analysis can be used as a data analytic tool to answer some questions of interest. For each example: What is the question of interest? Identify the response and the predictor variables.

9. Give examples of two variables that are positively correlated and two that are negatively correlated.

10. What is the purpose of ANOVA?

11. What are the assumptions for ANOVA?

12. What is the difference between t test and ANOVA test?