AMS 5 Practice 19 5142017 (8:009:05) Chapter 19, 1, 5, 6, 7 1. A survey organization is planning to do an opinion survey of 2,500 people of voting age in the U.S. True or false, and explain: the organization will choose people to interview by taking a simple random sample. 1) True; You dont want to poll the same people again, so you in effect draw at random without replacement. 5. (Hypothetical) A survey is carried out by the finance department to determine the distribution of household size in a certain city. They draw a simple random sample of 1,000 households. After several visits, the interviewers find people at home in only 653 of the sample households. Rather than face such a high nonresponse rate, the department draws a second batch of households, and uses the first 347 completed interviews in the second batch to bring the sample up to its planned strength of 1,000 households. The department counts 3,087 people in these 1,000 households, and estimates the average household size in the city to be about 3.1 persons. Is this estimate likely to be too low, too high, or about right? Why? 5) Too high, since there is a substantial nonresponse bias that favors larger families that are probably cooped up longer in their houses taking care of their larger families. 6. Ecstasy was a popular drug in the 1990s. It produced a sense of euphoria derisively called the yuppie high. One investigator made a careful sample survey to estimate the prevalence of drug use at Stanford University. Two assistants were stationed on the main campus plaza and instructed to interview all students who passed through at specified times. As it turned out, 39 of 369 students interviewed said they had used Ecstasy at least once. Does the investigators procedure give a probability sample of Stanford students? Answer yes or no, and explain.