Question 1184185
population mean = 3.45
population standard deviation = .20


z = (x - m) / s
z is the z-score
x is the raw score
m is the raw mean
s is the standard deviation.


formula becomes:


z = (3.85 - 3.45) / .2 = 2.


area to the right of a z-score of 2 is equal to .022750062.


that's the probability of the price of gasoline being greater than 3.85.


the probability of .022750062 rounds to .0228 as shown in the following diaplay of the z-score calculator by david m. lane.


<img src = "http://theo.x10hosting.com/2021/090604.jpg" >


the z-score calculator can work off the mean and standard deviation to give you the raw score, as shown.


the z-score calculator gives you the z-score if the mean is set to 0 and the standard deviation is set to 1.


here's the display when looking for the z-score.


<img src = "http://theo.x10hosting.com/2021/090605.jpg" >