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Unformatted text preview: confidence interval for the population mean days absent for sickness. 2 5 3 7 10 6 8 5 11 3 1 Since σ is unknown, a student – t table should be used. b. If the same confidence interval is used, how many employees should be in the random sample so that there is no more than 1 sick day of error? c. If Direct Marketing Industry, found that the national average for sick days is 6.5 days, are their employees healthier than the national average or can the company only assume they had a good year? Use α=.01 3. The average salary for a person in the business field on Long Island is $67,452, with a standard deviation, = $1,326. If you wanted to select the top 9 companies to apply for a job, what would the average salary of the top 9 companies have to be to be greater than $67,452 at α = .01. Compare that to a level of significance of α = .05. What would your opinion be comparing the 2 significance levels....
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- Spring '11
- Statistics, Mean, direct marketing industry