Question 1162147
the mean is 120.
the standard deviation is 25.


what % of the students scored above 170?


use the z-score formula of z = (x-m)/s
formula becomes:
z = (170 - 120) / 25
solve for z to get:
z = 50 / 25 = 2.0
look up z-score in z-score table to find that the area to the left of that z-score is equal to .97725
since you want the percent of students who scored above that z-score, then take 1 - .97725 to get the area  to the right of that z-score equal to get .02275.


multiply  that by 100 to get 2.275% of the students scored above 170.


here's the table i used.


<a href = "https://www.math.arizona.edu/~rsims/ma464/standardnormaltable.pdf" target = "_blank">https://www.math.arizona.edu/~rsims/ma464/standardnormaltable.pdf</a>