<span>A medical researcher wants to investigate the amount of time it takes for patients' headache pain to be relieved after taking a new prescription painkiller. She plans to use statistical methods to estimate the mean of the population of relief times. She believes that the population is normally distributed with a standard deviation of 18 minutes. How large a sample should she take to estimate the mean time to within 4 minutes with 97% confidence?
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n = [z*s/E]^2
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n = [2.17*18/4]^2 = 96 when rounded up
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Answer:
2cos^2u--1
1--2sin^2u
cos^2u--sin^2u
Step-by-step explanation:
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