A clinical study is designed to assess the average length of…
A clinical study is designed to assess the average length of hospital stay of patients who underwent surgery. A preliminary study of a random sample of 70 surgery patients’ records showed that the standard deviation of the lengths of stay of all surgery patients is 6.7 days. How large should a sample to estimate the desired mean to within 1 day at 95% confidence? (Round your answer up to the next higher whole number.)
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