T Scores

One of the most common standardized scores is T scores. Like Z scores, T scores are normally distributed and allow for consistent interpretation of a student’s relative performance on an individual test and across tests. While Z scores have a mean of 0 and a standard deviation of 1, T scores have a mean of 50 and a standard deviation of 10, where the mean and standard deviation are held constant.

To convert any raw score into a T score, first transform the score into a Z score and then use the following basic formula: T = 10 z + 50. To calculate the T score for a given score, it is important to first convert the raw score to a Z score, so that the ...