Answer Happy

Question 3. A prospective cohort study has been conducted to determine whether cell phone ownership among young children is related to sleep disorders during their high school years. 1000 children are recruited to study, 500 who are given a cell phone by their parents by grade 4 and 500 who are not. Five years later when the children enter high school (grade 9), they are all asked to complete a questionnaire to identify whether the suffer from a sleep disorder. Data from this study are summarized in the following contingency table (this question is 6 marks, total] Outcom Sleep disorder in grade YES NO I Total Exposure Ce phone by YES NO Total 150 80 230 350 320 670 00 00 1000 1) Do you think that the investigator's hypothesis makes sense theoretically? Justify your answer in a few sentences. [1 mark] 2) Calculate and interpret an appropriate measure of association to describe the relationship between the exposure and the outcome [1 mark]
Question 3 (continued) The investigators are worried that the above results may be modified or confounded by biological sex (males, females) measured in grade 4. Then then perform a stratified analysis of their data. This is shown below: Males Outcome Sleep disorder in grade 9 YES NO Total Exposure Cell phone byer 4 YES NO Total 100 40 140 150 210 360 250 250 500 I Females Outcome Sleep disorder in grade 9 YES NO Total Exposure Cell phone byer 4 YES NO Total 50 40 90 200 210 410 250 250 500 3) Re-calculate the measure of association for each of males and females (1 mark) 4) Based upon the results of your calculations, do you think that biological sex is asking as an effect modifier of the relationship between the exposure and the outcome? Why or why not? (1 mark) 5) Based on these results, is biological sex acting as a confounder? Why or why not? [1 mark) 6) What results would you present in your final report, given your findings (1 mark]