Statistics Homework Help

1. Which of the following designs is best for testing a causal relationship?

A. Cross-sectionalB. EcologicalC. Case-controlD. Case report

2. Which of these can serve as a unit of observation in the ecological study?

A. SchoolsB. HospitalsB. HouseholdsC. All of the aboveD. A and B 

3. Which of the following study designs is most efficient in studying a rare exposure?

A. Case-controlB. Cross-sectionalC. CohortD. B and A

4. Correlation coefficient (r) cannot yield both the direction and the strength of association between two quantitative variables.

A. TrueB. FalseC. None of the above

5. The independent t-test is:

A.  An inferential statistic that determines whether there is a statistically significant difference between  the proportions of two unrelated groups.  

B. An inferential statistic that determines whether there is a statistically significant difference between the means of two related groups. 

C. An inferential statistic that determines whether there are statistically significant differences between the means of two unrelated groups. 

D. An inferential statistic that determines whether there is a statistically significant difference between   the proportions of two related groups. 

6. The evidence against the null hypothesis gets stronger as the p-value gets:

A. Larger and largerB. Smaller and smallerC. None of the above

7. Which of these responses is not a criterion for an exposure to qualify as a risk factor:

A. There is a dose-response relationshipB. There is no temporality between exposure and diseaseC. The observed relationship between exposure and disease is not due to some source of error in design 

8. A professor at Simpson College studied alcohol use among college students. The results showed that 45% of males drank alcohol during the past week compared with 44% of women. What are the dependent and the independent variables in this study?

9. A new drug is proposed to lower total cholesterol. A randomized controlled trial is designed to evaluate the efficacy of the medication in lowering cholesterol. Forty participants are enrolled in the trial and randomly assigned to receive either a new drug or a placebo. The participants do not know which treatment they are assigned. Each participant is asked to take the assigned treatment for 8 weeks.

A. State the Research Question

B. State both the null and the alternative hypothesis

C. State the test statistic to be used, and why you consider it the most appropriate test.

D. Why do you think it necessary not to inform the participants about the treatment to which they are assigned?

10.  Dr. Clint wanted to predict the effects of gender (male vs. female) on diastolic blood pressure (high vs. low) among college students in New York State.

A. State the Research Questions

B. State both the null and the alternative hypothesis

C. State the test statistic to be used, and why you consider it the most appropriate test.