A random sample of Americans showed that 4 believe their health care is excellent. If the conservative margin of error was 12.5, what was the sample size?
a. 25
b. 36
c. 49
d. 64
Q. 2A random sample of 1001 Americans aged 18-24 years showed that 51 believe their health is extremely important. An approximate 95 confidence interval for the proportion of all 18-24 year olds who believe that their health is extremely important is
a. between 41 and 61.
b. between 46 and 56.
c. between 48 and 54.
d. between 50 and 52.
Q. 3A random sample of Americans at least 65 years old showed that 32 believe their health is extremely important. If the sample size was 100, approximately what was the margin of error?
a. 1
b. 5
c. 10
d. 15
Q. 4A randomly selected sample of 1,000 college students was asked whether they had ever used the drug Ecstasy. Sixteen percent (16 or 0.16) of the 1,000 students surveyed said they had. Which one of the following statements about the number, 0.16 is correct?
a. It is a sample proportion.
b. It is a population proportion.
c. It is a margin of error.
d. It is a randomly chosen number.
Q. 5Studies have shown that growing numbers of young girls are beginning to use steroids. At a committee hearing, a survey by the Centers for Disease Control and Prevention of high school students was cited, in which 7.3 percent of ninth-grade girls said they had used illegal steroids. One critic of the results objected to the methodology of the survey, which used an anonymous questionnaire and did not ask what substances were used. He suggested that some of the teenagers might have thought incorrectly that were using anabolic steroids. What type of bias is being raised by this issue?
Q. 6A telephone survey was planned to ask people whether they planned to watch the next Super Bowl. Explain why non-response bias may be a problem for this survey.
Q. 7A random sample of registered 500 voters was taken, and 80 responded that they had voted in the last presidential election. Explain why response bias may be a problem for this survey.
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