x tcdf y computes the CDF at y of the t-distribution with x degrees of freedom. 

tcdf=: 4 : 0
 assert. (%:x)>|y
 0.5 + y * (!-:x-1) * ((0.5,-:1+x) H. 1.5 x%~-*:y) % (%:o.x) * !<:-:x
)

   5 tcdf 2.01505 1.47588
0.95 0.899999


See also

Contributed by RogerHui.

Essays/t-Distribution CDF (last edited 2011-05-09 00:55:14 by RogerHui)