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. b) What is the probability that 2 of the next 3 cus

Algebra ->  Probability-and-statistics -> 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. b) What is the probability that 2 of the next 3 cus      Log On


   

Question 876253: Costumers in a department store are normally distributed with a mean age of 32.3 years and a standard deviation of 9.7 years.
b) What is the probability that 2 of the next 3 customers will be in their twenties? (2)
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi

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