Question

Determine the probability that a random smart phone user in the age range 13 to 55 is between 23 and 64.7 years old with approximate mean and standard deviation of 36.9 years and 13.9 years.

Answer 1

P(23<age<64.7) = P(age<64.7)-P(age<=23) = 0.8186

in excel

=NORM.DIST(64.7,36.9,13.9,1 )-- NORMDIST(23,36.9,13.9,1)