The tobacco industry closely monitors all surveys that involve smoking. One survey showed that among 850 randomly selected subjects who completed 4 years of college, 10.3% smoke (based on data from American Medical Association). The 80% confidence interval for the true percentage of smokers of all people who completed 4 years of college is closest to (0.900, 0.116) b. (0.245, 0.267) c. (0.397,0.457) d. (0.147, 0.219) e. (0.359,0.923) a.

A survey of 2450 golfers showed that 281 of them are left-handed. Construct a 90% confidence interval for the proportion of golfers that are left-handed. Question 10 options: (0.104, 0.125) (0.369, 0.451) (0.100, 0.130) (0.203, 0.293)

A 95% confidence interval for a population proportion, p, is 0.23 < p < 0.27. What was the sample proportion?

Suppose we wish to estimate the average number of hours per week that Americans watch TV. Use the following data from an SRS to find a 90% confidence interval: 30        64        49        40        21        58        9          43        39            43

A survey is taken of 250 students, and a P of 0.45 is found. The same survey is repeated with 1,000 students, and the same value is found. Compare the two 95% confidence intervals. What is the relationship? Is the margin of error for the second one four times smaller? How much smaller is it?

A random sample of high school seniors were asked whether they were applying for college. The resulting confidence interval for the proportion of students applying for college is (0.65,0.69). What is the margin of error?

A survey of 32,782 adults in 2004 indicated that 24.6% of adults were current smokers. A similar study conducted in 1995 of 40,000 adults indicated that 29.7% were current smokers. a. Find and interpret a point estimate of the difference between the proportion of current smokers in 1995, and the proportion of current smokers in 2004. b. A 95% confidence interval for the true difference is (-0.058,-0.045). Interpret. c. What assumptions must you make for the confidence interval i part b to be valid? (…) a. Find a point estimate of the difference between the proportion of current smokers in 1995 and the proportion of current smokers in 2004. (Round to three decimal places as needed.)

8.2 question 5).  In 2013, the Gallup poll asked 1,039 American adults if they believe there was a conspiracy in the assassination of President Kennedy and found that 634 believe there was a conspiracy ("Gallup news service," 2013). Estimate the proportion of American’s who believe in this conspiracy using a 98% confidence interval.

In a survey of 900 adults, 240 said that they watched the World Cup final on television. Using these sample statistics, calculate the margin of error, E, for a 90% confidence interval for the proportion of all adults that watched the World Cup final on television.   A. 0.019   B. 0.024   C. 0.029   D. 0.034