SOLUTION: Assume that systolic blood pressure readings are normally distributed with a mean of 122 and a standard deviation of 9.6. If 144 individuals are selcted at random, determine the p

Algebra ->  Probability-and-statistics -> SOLUTION: Assume that systolic blood pressure readings are normally distributed with a mean of 122 and a standard deviation of 9.6. If 144 individuals are selcted at random, determine the p      Log On


   

Question 375569: Assume that systolic blood pressure readings are normally distributed with a mean of 122 and a standard deviation of 9.6. If 144 individuals are selcted at random, determine the probability that the mean (systolic) blood pressure of these individuals will be less than 124.
I don't know where to begin!
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
The sampling distribution of the means would also be normally distributed with a mu+=+122 and standard deviation sigma%2Fsqrt%28n%29+=+9.6%2Fsqrt%28144%29+=+9.6%2F12+=+0.8. Then

=P%28Z+%3C+%28124+-+122%29%2F0.8%29+=+P%28Z+%3C+2.5%29. You can easily get the probability now by looking at a usual standard normal table.