Question

Weekly wages at a certain factory are

normally distributed with a mean of
$400 and a standard deviation of $50.
Find the probability that a worker
selected at random makes between
$500 and $550.


Need the answer as a % !!!

Answer 1

2.15%

Explanation:

If you were to get the z-score for both 500 and 550 and then get the probability of both those z-scores. After getting the probability you would subtract both probability and get your answer.

Z-score:

550-400/2=3

500-400/2=2

Probability:

3 (from the Z-table) is .9987

2 (from the Z-table) is .9772

.9987-.9772= .0215

.0215 as a percentage is 2.15%

Answer 2

Mean: 400

Standard deviation: 50

Check to see if 500 and 550 fall within the standard deviations:

400+2(50) =500

400+3(50) =550

These values lie between the 2nd and 3rd deviations, so

the value is 0.0235

Percentage: 2.35%

Hope it helps!