Daniel and Shanice each improved their yards by planting daylilies and ivy. They bought their supplies from the same store. Daniel spent $123 on 9 daylilies and 7 pots of ivy. Shanice spent $102
on 6 daylilies and 8 pots of ivy. What is the cost of one daylily and the cost of one pot of ivy?

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