Two students took the same statistics test Convert their sco

Two students took the same statistics test. Convert their scores to percentiles and plot on a chart. You will need the z-table.

Stat test results

X= 73.0

s=8.0

Fred scored a 79

Jennifer score a 68

Solution

Mean ( u ) =73
Standard Deviation ( sd )=8
Normal Distribution = Z= X- u / sd ~ N(0,1)                  
a)
P(X = 79) = (79-73)/8
= 6/8= 0.75
= P ( Z <0.75) From Standard Normal Table
= 0.7734                  
b)
P(X = 68) = (68-73)/8
= -5/8= -0.625
= P ( Z <-0.625) From Standard Normal Table
= 0.266