A 95% confidence interval for p, the proportion of all shoppers at a large grocery store who purchase cookies, was found to be (0.236, 0.282).

Which of the following is a correct statement?

A 95% confidence interval for p, the proportion of all shoppers at a large grocery store who purchase cookies, was found to be (0.236, 0.282).

Which of the following would be true about a 98% confidence interval constructed using the same data?

An SRS of 50 students at a large middle school are asked, “Do you have a television in your bedroom? Twenty-eight of the students responded “yes.”

If ƥ = the proportion of students who answered “yes,” what is the standard error of ƥ ?

The college newspaper of a large Midwestern university periodically conducts a survey of students on campus to determine the attitude on campus concerning issues of interest. Pictures of the students interviewed along with quotes of their responses are printed in the paper. Students are interviewed by a reporter “roaming” the campus selecting students to interview “haphazardly.” On a particular day the reporter interviews five students and asks them if they feel there is adequate student parking on campus. Four of the students say, “no.” Which of the following conditions for inference about a proportion using a confidence interval are violated in this example?

I. The data are an SRS from the population of interest.

II. The population is at least ten times as large as the sample.

III. np̂ ≥ 10 and n(1− p̂) ≥10 .

6. You want to estimate the proportion of students who meet the state standards on the SAT with a 90% confidence interval. You don’t have a sample proportion to use yet. If you want the margin of error to be no more than 10%, you will need a minimum sample size of approximately

The government claims that 88% of students work during their summer break from college. A random sample of 500 students gave a proportion of 80% and a 95% confidence interval of (.76, .83). Which of the following is a correct interpretation of the 95% level?

Janice and her cousin Linda are a little competitive about the relative merits of their home towns. One contest they had was to determine who had more rainy days. They found weather records on the internet and each of them randomly selected 60 days from the past 5 years. Janice found that there had been measurable rainfall on 17 of the 60 days she selected for Minooka (M), and Linda found that there had been measurable rainfall on 12 of the 60 days she selected for Green Bay (G). They intend to perform a confidence interval estimating the true difference of proportion of rainy days between Minooka and Green Bay. Which expression should they use to estimate the standard deviation for the sampling distribution of p̂_M - p̂_G

A city planner wants to estimate the proportion of city residents who commute to work by subway each day. A random sample of 30 city residents was selected, and 28 of those selected indicated that they rode the subway to work. Is it appropriate to assume that the sampling distribution of the sample proportion is approximately normal?

Lila and Robert attend different high schools. They will estimate the population percentage of students at their respective schools who have seen a certain movie. Lila and Robert each select a random sample of students from their respective schools and use the data to create a 95 percent confidence interval. Lila’s interval is (0.30,0.35), and Robert’s interval is (0.27,0.34). Which of the following statements can be concluded from the intervals?