A medical researcher wants to investigate the amount of time it takes for patients' headache pain to be relieved after taking a new prescription

A medical researcher wants to investigate the amount of time it takes for patients' headache pain to be relieved after taking a newprescription 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 25 minutes. How large a sample should she take to estimate themean time to within 3 minutes with 90% confidence? Sample Size =