Question

In class A, John got 85 for his first test John's class mean was 75 and standard deviation was 5. In class B, Kathy got 80 in her first test. Kathy's class mean was 50and standard deviatoin was 10. In a fair comparison of the two studens in two different classes who did better in his or her test. a. John b. Kathyc. same d. none of the above

Answer 1

b. Kathy

Explanation:

We compare each of their score by how far away from the mean when in term of the standard deviation. Using the following formula

`(x - \mu)/(\sigma)`

For John he is (85 - 75)/5 = 2.

For Kathy she is (80 - 50)/10 = 3.

Since Kathy is 3 standard deviation better than her class' average, while John is only 2's. We conclude that Kathy did better.