3.5.3.2.23 Tcdf

Description

Computes the probabilities of the specified tail type tail, associated with a cumulative distribution function of Student's t-distribution with the degree of freedom df.

Syntax

double prob = tcdf(double t, double df[, int tail])

Parameters

t

Input, the value of the Student's t variate.[ -\infty,+\infty]

df

Input, the degrees of freedom, \nu , of the Student's t-distribution.(df\geq 1)

tail

Input, Optional. The tail probability type using for the Student's t-distribution
  • 1 = the for upper tail probability
  • 2 = the lower tail probability (Default if not set)
  • 3 = the two tail (significance level) probability
  • 4 = the two tail (confidence interval) probability

prob

Output, the probability.

Example

tcdf(38.9036068506926,30, 3)=;     // ANS: 3.110454711125E-27