SOLUTION: 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 statis
Algebra ->
Probability-and-statistics
-> SOLUTION: 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 statis
Log On
Question 1140009: 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 25 minutes. How large a sample should she take to estimate the mean time to within 4 minutes with 90% confidence? Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! Half-interval is a z(.90)*sigma/sqrt(n)=4
this is 1.645*25/sqrt(n)=4
1.645*25=4 sqrt(n)
41.125=4 sqrt(n)
10.28125=sqrt(n)
n=105.70 or 106 rounding up
