SOLUTION: The loan officer rates applicants for credit. Ratings are normally distributed. The mean is 240 and the standard deviation is 30. If 36 applicants are randomly chosen, what is the

Algebra ->  Probability-and-statistics -> SOLUTION: The loan officer rates applicants for credit. Ratings are normally distributed. The mean is 240 and the standard deviation is 30. If 36 applicants are randomly chosen, what is the       Log On


   



Question 259029: The loan officer rates applicants for credit. Ratings are normally distributed. The mean is 240 and the standard deviation is 30. If 36 applicants are randomly chosen, what is the probability that they will have a rating between 230 and 260?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
The loan officer rates applicants for credit. Ratings are normally distributed. The mean is 240 and the standard deviation is 30. If 36 applicants are randomly chosen, what is the probability that they will have a rating between 230 and 260?
------------------
Find the t-score of 230 and of 260:
t(230) = (230-240)/[30/sqrt(36)] = -2
---------------
t(260) = (260-240)/[30/sqrt(36)] = 4
-----------------------------------------
P(230<=x<=260) = P(-2<= t <= 4 with df = 35) = 0.9732
====================================
Cheers,
Stan H.