11.1 t-test for a paired difference in marble masses
Students select two marbles from a box, one from each side of a divided box. One side includes marbles less than or equal to 5.2 grams, the other side contains marbles greater than 5.2 grams. Data from spring 2026 demonstrated that students could distinguish which marble was more massive using a paired t-test and an alpha of 0.05. The ability of Desmos to display the t-distribution graphically (and calculate t-ciritical from data) allows for the graphical display of the result. The t-test capability displays the p-value based directly on the data. Desmos has become a powerful tool for displaying statistical results graphically. Calculating t-critical involves using tdist(n-1).inversecdf(0.975) for a 95% confidence interval. In the above example the test is an independent samples t-test, not a pairwise test of the differences. Desmos To do a pairwise t-test the data has to be the pairwise differences, which can also be done as seen above. Desmos This term ...