Question

The average hourly wage of workers at a fast food restaurant is $7.50/hr with a standard deviation of $0.75. Assume that the distribution is normally distributed. If a worker at this fast food restaurant is selected at random, what is the probability that the worker earns between $7.50 and $8.25?

Answer 1

The average hourly wage of workers at a fast food restaurant is $7.50/hr with a standard deviation of $0.75. Assume that the distribution is normally distributed. If a worker at this fast food restaurant is selected at random, what is the probability that the worker earns between $7.50 and $8.25?

z = (x-µ)/σ

Z value for 7.50, z=(7.50-7.50)/0.75 =0.0

Z value for 8.25, z=(8.25-7.50)/0.75 =1

P( 7.50<x<8.25) = P( 0<z<1)= P( z <1) – P( z < 0)

=0.8413 – 0.5

=0.3413

Excel function used:

P( z <1): =NORM.S.DIST(1,TRUE)

P( z <0): =NORM.S.DIST(0,TRUE)