SOLUTION: For the first 7 months of the year, the average precipitation in Toledo, Ohio is 19.32 inches. If the average precipitation is normally distributed with a standard deviation of 2.4

Algebra ->  Probability-and-statistics -> SOLUTION: For the first 7 months of the year, the average precipitation in Toledo, Ohio is 19.32 inches. If the average precipitation is normally distributed with a standard deviation of 2.4      Log On


   

Question 973667: For the first 7 months of the year, the average precipitation in Toledo, Ohio is 19.32 inches. If the average precipitation is normally distributed with a standard deviation of 2.44 inches, find the following probabilities:
A) a randomly selected year will have precipitation greater than 18 inches for the first 7 months
B) five randomly selected years will have an average precipitation greater than 18 inches for the first 7 months
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
mean=19.32 inches
sd=2.44 inches
z>(18-19.32)/2.44 ;;; This should have a probability of 50-84%
z>(-1.32)/2.44 or z> -0.540
P=0.706
z>(-1.32)*sqrt(5)/2.44 The SE is 2.44/sqrt(5). I inverted in division and put sqrt (5) in numerator.
z>-1.209
P=0.887. This is expected, because now we are looking at 5 random years ALL of which have an expected greater than 18 inch amount.