Education Technology

Solution 11717: Calculating the Inverse Student-T (invT) Probability on the TI-83 Plus Family of Graphing Calculators.

How can I calculate the inverse student-T probability on the TI-83 Plus family of graphing calculators?

The Inverse Student-T is usually used for determining probabilities of population means from sampled distributions when the standard deviation of the population is unknown. Specifically, t = (x-u)*sqrt(n)/s with n-1 degrees of freedom and where x is the sampled mean, u is the population mean, s is the sample standard deviation, n is the sample size, and the population is Gaussian.

The command for this function is under the DISTR menu. Please refer to the instructions provided below given the below data.

Area = 0.68759
DF = 18

1) Press [2nd][DISTR]
2) Press [4] to select 4:InvT(
3) Press [0] [.] [6] [8] [7] [5] [9] [,] [1] [8] [ ) ] 
4) Press [ENTER] to display the answer of 0.4975567034

Please see the TI-83 Plus Family guidebooks for additional information.