A national survey was initiated and intended to capture the prevalence of HIV in the postHAART (Highly active anti-retroviral therapy) era of treatment. Out of a sample of 1,483 participants, a total of 241 were found to be HIV positive. A) Calculate a SE. B) Construct a 95% confidence interval about the estimate.

2. Researchers are interested in conducting an observational study investigating the relationship between hepatitis C and early mortality in HIV positive patients. The following table represents the findings from the study after a follow-up time period of 15 years. Deceased Not Deceased Total Hepatitis C + 421 348 769 Hepatitis C - 425 820 1245 Total 846 1168 2014 A) Calculate the mortality rate in the exposed and unexposed. B) Is mortality a measure of incidence or prevalence?

3. A research team is hired to investigate the prevalence of periodontal disease in a rural county with a low average socio-economic status. The team is given the task of surveying the area, and providing a brief examination of participants to correctly identify cases of periodontal disease and estimate an overall prevalence. If the team identifies an overall prevalence of above 25%, the sponsoring organization is to initiate an active campaign promoting healthy dental practice. Out of 2,879 participants surveyed, 589 were identified to have periodontal disease. A) Conduct a formal test for detecting if the prevalence of periodontal disease in the sample is significantly different from the minimum prevalence for intervention. Use an alpha level of 0.01. B) Interpret your conclusions.

4. A researcher is interested in investigating the power of his statistical test analyzing the success rate of increasing forced vital capacity (FVC) in children with asthma. Suppose the researcher conducted a z test for significance with a SRS of 74 on a population with a mean FVC of 84% with a null hypothesis that mean FVC was equal to 76%. The prior research determined the standard deviation was 1.2%. What was the power of the test at 95% confidence?