Which scores have a mean of 100 and a standard deviation of 15?

Which scores have a mean of 100 and a standard deviation of 15?

• A. Percentile scores
• B. Z-scores
• C. T-scores
• D. Standard Scores m=100 sd=15

Answer: (D)

Standard scores are created by transforming raw scores so they sit on a common scale with a specified mean and spread. A scale with mean 100 and standard deviation 15 is a classic example used for many ability and achievement tests, so a score of 100 is the average and about 15 points is one standard deviation from the mean. This is different from z-scores, which are scaled to mean 0 and standard deviation 1, or T-scores, which typically have mean 50 and SD 10. Percentile scores, on the other hand, indicate relative rank (the percentage below a given score) and don’t have a fixed mean or standard deviation. So the description of a standard score with mean 100 and SD 15 matches the concept of standard scores.

Standard scores are created by transforming raw scores so they sit on a common scale with a specified mean and spread. A scale with mean 100 and standard deviation 15 is a classic example used for many ability and achievement tests, so a score of 100 is the average and about 15 points is one standard deviation from the mean.

This is different from z-scores, which are scaled to mean 0 and standard deviation 1, or T-scores, which typically have mean 50 and SD 10. Percentile scores, on the other hand, indicate relative rank (the percentage below a given score) and don’t have a fixed mean or standard deviation.

So the description of a standard score with mean 100 and SD 15 matches the concept of standard scores.