A small pyramid has 3 stones at the top and 2 more stones in each layer below this. If the pyramid has 19 layers, how many stones are in the pyramid?

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

Lowest fraction using common term 28/35

With this problem-elena cycled to school. find the distance travelled by elena if her bicycle wheels rotated 840 times and the radius is 0.25 m.