SOLUTION: Costumers in a department store are normally distributed with a mean age of 32.3 years and a standard deviation of 9.7 years. a) What is the probability that the next customer t

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Question 876252: Costumers in a department store are normally distributed with a mean age of 32.3 years and a standard deviation of 9.7 years.
a) What is the probability that the next customer that enters the store will be in their twenties?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi

Population: mean age of 32.3 years and a standard deviation of 9.7 years.

P(20 ≤ x ≤ 29  ) = P( -1.268 ≤  z  ≤  -.340)

                 = P( z ≤  -.340) -P(z  ≤ -1.268)

                 = .3669 - .1024 = .2645 

n = 3

b) P(2) = 3C2(.2645)^2(.7355)^1