A National Institute of Health survey of 40467 U. S adults found that 3156 of them experienced at least one major depressive episode in the previous year. Make a 95% confidence interval for the proportion of all U. S. adults who experienced depression in that year. (Source: https://www. nimh. nih. gov/health/statistics/major-depress ion)

Researchers are conducting experiments to determine the role of alcohol in the development of depression. after the study is complete, they determine that the relative risk of developing depression is 1.55 with a 95 % ci of 1.2 -1.9. each group is then divided into nonsmokers and smokers. the relative risk for the nonsmokers is 1.12 with a 95% ci of 0.87-1.37. the relative risk for the smokers is 1.7 with a 95 % cl of 1.5-1.9. what type of bias may affect this study? a. procedure bias b. recall bias c. selection bias d. confounding e. lead-time bias