For a sample of n = 30 scores,X = 45 corresponds to z = 1.50 and X = 40 corresponds to z = +1.00.What are the values for the sample mean and standard deviation?
A)M = 35 and s = 10
B)M = 30 and s = 15
C)M = 35 and s = 15
D)M = 30 and s = 10

Question

For a sample of n = 30 scores,X = 45 corresponds to z = 1.50 and X = 40 corresponds to z = +1.00.What are the values for the sample mean and standard deviation?​
A)​M = 35 and s = 10
B)​M = 30 and s = 15
C)​M = 35 and s = 15
D)​M = 30 and s = 10

Quizplus · Accepted Answer

The z-score formula is z = (X - M) / s. Solving the equations for the given z-scores and X values, we find M = 30 and s = 10.

For a Sample of N = 30 Scores,X = 45