Explain how alfred's argument contradicts his initial assumption proving that the sum cannot be rational. a) if c is rational, either b or a would have to be rational as well. b) if a is rational, either b or c would have to be rational as well. c) if b is irrational, the difference of two rational numbers could never be equal to it. d) if a + b is rational, then a and a could be either rational or irrational.

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