Question

which is better: a score of 580 on a test with a mean of 430 and a standard deviation of 130, or a score of 93 on a test with a mean of 75 and a standard deviation of 15? explain your choice. show the z score formula used.

Answer 1

First Test

mu = mean = 430

sigma = standard deviation = 130

z = (x - mu)/sigma

z = (580 - 430)/130

z = 1.15 approximately

-------------

Second Test

mu = mean = 75

sigma = standard deviation = 15

z = (x - mu)/sigma

z = (93 - 75)/15

z = 1.20 exactly

-------------

The first test has a z score of about z = 1.15, while the second z score is exactly z = 1.20

The second test score is better among its peers, compared to the the first test score among its peers.