Find the probability that a worker selected at random from the city makes the following weekly wage

Question

According to the data released by the Chamber of Commerce of a certain city, the weekly wages of factory workers are normally distributed with a mean of $720 and standard deviation of $50. Find the probability that a worker selected at random from the city makes the following weekly wage. (Round your answers to four decimal places.)

(a) less than $720

 

(b) more than $845

 

(c) between $620 and $770

Answer 1

n(720, 50)

a) 50%

b) p(x>850)= 100- 99.5%= 1/2 % chance

z= (850-720)/50=13/5=2.6

c) p(620<x<770) z =1 and - 2

corresponding areas, with the empircal rule are .34 and .475

add them = .825 = 82 1/2 %