A recent poll of 700 people who work indoors found that 278 of them smoke. If the researchers want to be 98% confident of their results to within 3.5%, how large a sample is necessary?
A previous analysis of paper boxes showed that the standard deviation of their lengths is 7 millimeters. A pakcer wishes to find the 90% confidence interval for the average length of a box. How many boxes does he need to measure to be accurate within 1 millimeters?
A report states that 42% of home owners had a vegetable garden. How large a sample is needed to estimate the true proportion of home owners who have vegetable gardens to within 5% with 99% confidence?
A college believes that 28% of applicants to that school have parents who have remarried. How large a sample is needed to estimate the true proportion of students who have parents who have remarried to within 5% with 95% confidence?
Choose one answer.
In a sample of 855 bartenders, 48% heard complaints from patrons about work. If the margin of error was 4.4%, what was the confidence level that was used?
A researcher conducted a study of the access speed of 40 hard drives and concluded that his maximum error of estimate was 24. If he were to conduct a second study to reduce the maximum error of estimate to 6, about how many hard drives should he include in his new sample?
A report states that 38% of home owners had a vegetable garden. How large a sample is needed to estimate the true proportion of home owners who have vegetable gardens to within 3% with 98% confidence?
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