Question

2. Suppose for a sample with a standard deviation of 10, a score of X = 44 corresponds to a z-score of -0.50. Based on this info, what is the sample mean?

3. Which of the following exam scores should lead to the better grade? Explain your answer.

A. A score of X = 55 on an exam that has a mean of 60 and a standard deviation of 5.

B. A score of X = 40 on an exam that has a mean of 50 and a standard deviation of 20.

Answer 1

2)

z = ( x - ) /

-0.5 = ( 44 - ) / 10

= 49

3)

z = (X - Mean) / SD

For X = 55

z = ( 55 - 60) / 5

= -1

For X = 40,

z = ( 40 - 50) / 20

= -0.5

Since z-score for X = 40 is larger than z-score for X = 55,

X = 40 exam score should lead to better grade.