Overview
Please review my incorrect answers(written in pencil) for the midterm. Correct answers written in Pen. Then In a separate word document:
- First insert a picture of the question you got wrong on your exam (I will provide) .
- Second, provide the correct answer (If this is multiple choice, the correct answer is likely already circled).
- Third, we need you to explain in detail why your original answer is incorrect and why the correct answer is correct. You will do this by defining the concepts that are involved in the problem and applying them to the question. PLEASE REFER TO EXAMPLE CORRECTIONS BELOW FOR WHAT YOU SHOULD SUBMIT. please be critical in the explanations you provide
Example;
- What are the odds of disease among the exposed?
- -Original answer: 345/1000 = 0.345
- -Correct answer: 345/68 = 5.07
- -Explanation: The main concepts evaluated by this problem are understanding of measures of associations in various study designs. In my original answer for part A, I initially thought this was a cohort study. In cohort studies, we calculate risk ratios or rate ratios because these study designs give us incidence data. I originally calculated A/A+B+C+D, which is incorrect. This is not a formula that we have learned in class and I'm not sure what led me to use this formula. The closes thing this formula represents would be a prevalence among the whole same since our denominator is everyone in the sample but even then the numerator would be incorrect. Instead of using this formula, I should have used the odds ratio formula because as noted in Part A this is in fact a cross sectional study which gives us prevalence data and therefore our measure of association would be an odds ratio. The concepts of odds is that quantify the likelihood that something happens out of the likelihood that something doesn't happen. Specifically in this question we are asked about the odds of disease among the exposed. This means we are being asked to quantify the likelihood that the among those who are exposed they get the disease out of the likelihood that among those who are exposed they don't get the disease. The number of exposed people who get the disease is in cell A and the number of exposed people who don't get the disease is B. This is all the information we need for an odds ratio so we use the formula A/B which will give us the odds of a disease among the exposed. This represents the number of people in the exposed group who have the disease divided by the number of people in the exposed group who do not have the disease. The correct answer therefore is 345 (number of people who are exposed and have asthma) divided by 68 (the number of people who are exposed and don't have asthma). The odds of asthma among the exposed is therefore 5.07.