Question

Raul received a score of 79 on a history test for which the class mean was 70 with a standard deviation of 5. He received a score of 70 on a biology test for which the class mean was 70 with standard deviation 6. On which test did he do better relative to the rest of the class?

Answer 1

Solution :

Given that ,

mean = = 70 ( history)

standard deviation =  = 5

x = 79

Using z-score formula,

z = x - /   

z = 79 - 70 / 5

z = 1.80 ( history)

mean = = 70 ( biology)

standard deviation =  = 6

x = 70

Using z-score formula,

z = x - /   

z = 70 - 70 / 6

z = 0  ( biology)

History test did he do better relative to the rest of the class, because history test z-score 1.80 larger than biology test z-score 0.