Chapter 11: Q. 11.34 (page 460)
Obtain a sample size that will ensure a margin of error of at most the one specified.
Margin of error
Confidence level
Short Answer
The required sample size is
Chapter 11: Q. 11.34 (page 460)
Obtain a sample size that will ensure a margin of error of at most the one specified.
Margin of error
Confidence level
The required sample size is
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Get started for freeObtain a formula for the margin of error, , in estimating the difference between two population proportions by referring to Step 2 of Procedure on page 472 .
A Wall Street Journal article, titled "Hypertension Drug Linked to Cancer," reported on a study of several types of high-blood-pressure drugs and links to cancer. For one type, called calcium-channel blockers, of elderly patients taking the drug developed cancer. For another type, called beta-blockers, of other elderly patients developed cancer. Find a confidence interval for the difference between the cancer rates of elderly people taking calcium-channel blockers and those taking beta-blockers. Note: The results of this study were challenged and questioned by several sources that claimed, for example, that the study was flawed and that several other studies have suggested that calcium-channel blockers are safe.
Obtain a sample size that will ensure a margin of error of at most the one specified.
Margin of error
Confidence level
Refer to the study on ordering vegetarian considered in Examples 11.8-11.10.
a. Without making a guess for the observed values of the sample proportions, find the common sample size that will ensure a margin of error of at most for a confidence interval. Hint: Use Exercise 11.133.
b. Find aconfidence interval for if, for samples of the size determined in part (a), of the men and of the women sometimes order veg.
c. Determine the margin of error for the estimate in part (b), and compare it to the required margin of error specified in part (a).
Smallpox Vaccine. ABCNEWS.com published the results of a poll that asked U.S. adults whether they would get a smallpox shot if it were available. Sampling, data collection, and tabulation were done by TNS Intersearch of Horsham, Pennsylvania. When the risk of the vaccine was described in detail, in of those surveyed said they would take the smallpox shot. According to the article, "the results have a three-point margin of error" (for a confidence level). Use the information provided to obtain a confidence interval for the percentage of all U.S. adults who would take a smallpox shot, knowing the risk of the vaccine.
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