I see 2 options.
1. store some values in the matrices
2. Compute the probability and cumulative probability by using formulas. The accuracy is in this case limited since the numerical integration is used and strongly depends on value of DoF, n<5 provides little bit worse results compared to the table..
example: n = 10, x = 2.3
p_t(10,2.3) = 0.0377
cumulative distribution function (= alpha, A)
CDF_t (10,2.3) = 0.0221 (or 97,79%)
Unfortunately there is no way how to exactly calculate t-value since the solver in 5800p doesn't support the integration, e.g. you know n = 15 and ta = 2.602 and you need to know corresponding alpha - in this case the alpha = 0.01.
Maybe there exists numerical method for such calculation.
Edited by pan.gejt, 07 November 2019 - 04:16 PM.