A colony of amoebas is being studied. The mass of the colony triples every day. On Day x of the study, the colony has a mass of 3 ^ x mg. a. What is the mass of the colony on Days 3, 2 and 1? What is the mass of the colony on Day 0, when the study begins? Show your work .

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