Finding the tscore is a popular way of determining whether differences in the means of two sample populations are statistically significant. If, for instance, we had a group of high school students that watches TV every day and a second group of high school students that reads instead, ttests would help us to determine whether differences in their GPAs are statistically significant, or if the differences can be attributed to random variation. Your TI83 Plus can save you a great deal of time in calculating the tscore.

Hit the "Stat" button, and enter the data into lists L1 and L2.

Select, under the "Stat" category, the "Tests" button, and press 2 for "TTest."

Select the option that µ1 does not equal µ2. This is the hypothesis that the averages of the two groups do have statistically significant differences. Select L1 and L2 for your data lists.

Select "Calculate," and hit Enter. The calculator will deliver your tscore, as well as the degrees of freedom of the calculation and the pvalue, or the probability that the differences between your sample means are coincidental.

Refer to a table of pvalues, tscores, and degrees of freedom and use the table, for a particular pvalue, to determine whether or not your tscores indicate statistically significant differences between two groups.