This is Assignment 3 for all sections. The due date will be announced in each section during class. Once all the assignments are collected, the solution will be posted on the web.
Question 1: We might expect states with more poverty to have fewer doctors. The below table gives data on the percent of each state's residents living below the poverty line and on the number of M.D.'s per 100,000 residents in each state.
|Poverty||M.D.'s per||Poverty||M.D.'s per|
Question 2: The National Halothane Study was a major investigation of the safety of anesthetics used in surgery. Records of over 850,000 operations performed in 34 major hospitals showed the following death rates for four common anesthetics.
Question 3: People who eat lots of fruits and vegetables have lower rates of colon cancer than those who eat little of these foods. Fruits and vegetables are rich in "antioxidants" such as vitamins A, C, and E. Will taking antioxidants help prevent colon cancer? A clinical trial studied this question with 864 people who were at risk of colon cancer: The subjects were divided into four groups: daily beta carotene, daily vitamins C and E, all three vitamins every day, and daily placebo. After four years, the researchers were surprised to find no significant difference in colon cancer among the groups.
Question 4: At a party there are 30 students over age 21 and 20 students under age 21. You choose at random 3 of those over 21 and separately choose at random 2 of those under 21 to interview about attitudes toward alcohol. You have given every student at the party the same chance to be interviewed: what is that chance? Why is your sample not an SRS?