Question

Help normal distributions

Answer 1

0.0215

Explanation:

The average weekly wage is $400 and the standard deviation is:

$50

The z-score for $250 is given by:

`z = (x - \mu)/( \sigma)`

Plug in the values to get:

`z = (250 - 400)/( 50) = - 3`

The z-score of $300 is

`z = (300 - 400)/( 50) = - 2`

The probability of earning less than:

$250 is

P(X<250)=0.0013, we got this by reading -3 under zero on the standard normal distribution table.

Similarly:

P(X<300)=0.0228

P(250<X<300)=0.0228-0.0013=0.0215

Therefore the probability that a workeep makes between 250 and 300 dollars is 2.15%