A T-Score is a type of standardized test statistic. The T-score formula allows you to take an individual test taker’s score and transform it into a standardized form to help you compare that score with others’ scores more easily.
For testing analysis purposes, a T-Score is a standard score shifted and scaled to have a mean of 50 and a standard deviation of 10. Using a T-score formula is very helpful if you have a small group of scores to compare (usually less than 30).
The formula for determining a T-score is:
t = (sample mean - population mean) ÷ (standard deviation ÷ √sample size)
In general, the larger the T-score, the larger the difference between the scores. A smaller T-Score tells you that scores are not significantly different from average.