Exam 10: Estimating Proportions With Confidence

Use the following information for questions: A television station plans to ask a random sample of 400 city residents if they can name the news anchor on the evening news at their station. They plan to fire the news anchor if fewer than 10% of the residents in the sample can do so. Suppose that 12% of city residents in the sample could name the anchor when asked. -What is the value of the point estimate for the population proportion of city residents who can name the news anchor on the evening news at their station?

Use the following information for questions: Data is to be gathered to estimate the proportion of residents who will vote for Mr. Treehouse in the coming city election. A random sample of 650 voters is interviewed and 306 of them say that they will support Mr. Treehouse. -What is the standard error of the sample proportion?

Use the following information for questions: A survey at a large public university reveals that many students hold a (part-time) job while going to college. Out of 127 female students surveyed, 95 have a job and out of 143 male students, 97 have a job. -What is the standard error of the estimate?

In a past General Social Survey, 23% of a random sample of 591 women answered yes to the question, "Have you ever been punched or beaten by another person?" Calculate an approximate 95% confidence interval for the proportion of all Americans who have been punched. Use the approximate margin of error (or the "95% margin of error").

Use the following information for questions: A television station plans to ask a random sample of 400 city residents if they can name the news anchor on the evening news at their station. They plan to fire the news anchor if fewer than 10% of the residents in the sample can do so. Suppose that 12% of city residents in the sample could name the anchor when asked. -Explain in your own words what the 95% confidence level implies.

Use the following information for questions: In a nationwide survey of n = 1,030 adults, 6% answered yes to the question "During the last year did anyone break into or somehow illegally get into your home or apartment?" -A 99% confidence interval for the proportion of all Americans who had their homes broken into is

Use the following information for questions: Suppose that a confidence interval for a population proportion p is to be calculated. For each confidence level find the appropriate z* multiplier. -The z* multiplier for a 60% confidence interval is

A sample of n = 168 students was asked, "Do you believe in love at first sight?" The choices below show confidence intervals, in scrambled order, for 90%, 95%, 98%, and 99% confidence levels for the population proportion who would answer yes. Which choice gives the 99% confidence interval?

In a poll of n = 200 randomly selected individuals, 60 people said they are opposed to the death penalty for persons convicted of murder. Which choice correctly shows the calculation of the margin of error for a 95% confidence interval for the population proportion opposed to the death penalty?

Use the following information for questions: Suppose that a 95% confidence interval for the proportion of teen drivers who were involved in a car accident is found to be (0.1425, 0.2875). -Does the 95% confidence level imply that P(0.1425 < p < 0.2875) = 0.95?

Use the following information for questions: In a past General Social Survey, 87% of a random sample of n = 990 respondents answered yes to the question "Would you approve of an adult male punching a stranger if the stranger had broken into the man's house?" -A 90% confidence interval for the proportion of all Americans who approve of punching an intruder is

Use the following information for questions: A 95% confidence interval for the proportion of young adults who skip breakfast is found to be 0.20 to 0.27. -Which of the following is the correct interpretation of the 95% confidence interval?

Use the following information for questions: A 95% confidence interval for p the proportion of supermarket customers who do not buy house-brand products at all is calculated and turns out to be: (0.18, 0.46). -The point estimate of p equals 0.40.

Use the following information for questions: Many people now-a-days use e-mail to communicate with family and friends and as a primary source of communication at their job. Is there a difference between the use of e-mail for men with a college education and those without? A survey in a large city reveals that out of 230 males with a college degree, 212 use e-mail more than twice a day. Out of the 150 without a college education, 122 use e-mail more than twice a day. -Calculate a 98% confidence interval for the difference in proportions.

You plan to determine an approximate 95% confidence interval for a population proportion; you plan to use a conservative margin of error of 10%. How large a sample size do you need?

You plan to use a conservative margin of error of 2%. How large a sample size do you need?

A CBS News poll taken in January 2010 asked a random sample of 1,090 adults in the US "Do you think the federal government is adequately prepared to deal with a major earthquake in the United States, or not?"A 95% confidence interval for the proportion of the population that thinks the government is prepared is .31 to .37. Based on this result, which one of the following statements is false?

Use the following information for questions: Data is to be gathered to estimate the proportion of residents who will vote for Mr. Treehouse in the coming city election. A random sample of 650 voters is interviewed and 306 of them say that they will support Mr. Treehouse. -Is it reasonable to conclude that Mr. Treehouse may win the election?

Use the following information for questions: Some statistical procedures move from population to sample; some move from sample to population. For each of the following procedures, determine the correct direction. -Sampling distributions take information from the ___________ to the ____________.

The multiplier for a confidence interval is determined by