Joe got a 78 on his test in biology the mean score was 80 wi

Joe got a 78 on his test in biology. the mean score was 80 with a standard deviation of 5 points. Amy got an 83 on her test in Chemistry. The mean score was 88 with a standard deviation of 8 points. what were their Z-scores? Who did relatively better?

Solution

As

z = (x - u)/sigma

Then for Joe,

z(Joe) = (78-80)/5 = -0.4 [ANSWER]

For Amy,

z(Amy) = (83-88)/8 = -0.625 [ANSWER]

As -0.4 > -0.625, then Joe did relatively better. [ANSWER]