i dont get this

Question

how to compute P(-1.22<t<1.22) with 14 degrees of freedom

Answer 1

Use a calculator or other technology (you can find t statistic calculators online) to find the left-side percentage for a t-score of 1.22 and 14 degrees of freedom: .8787. This leaves .1213 in the tail to the right. Therefore, from t = -1.22 to 1.22, the probability will be 1- 2(.1213).