| Property | Value |
|---|---|
| Hex Value | $EF13 |
| Categories | |
| Localizations |
|
invT(
Overview
Computes the inverse cumulative student-t probability function specified by degree of freedom, df for a given area under the curve.
Availability: Token available everywhere.
Syntax
invT(area,df)
Arguments
| Name | Type | Optional |
|---|---|---|
| area | ||
| df |
Location
2nd, distr, DISTR, 4:invT(
Description
invT( is the inverse of the cumulative Student t distribution function: given a probability p and a specified degrees of freedom v, it will return the number x such that tcdf(E-99,x,v) is equal to p
:invT(.95,24
1.710882023
Advanced
invT( is meant for use with so-called "one-tailed' tests; for two-tailed tests, the proper expression to use (corresponding to the inverse of tcdf(-x,x,v)) is invT(.5(1+p),v)
Formulas
Unlike the tpdf( and tcdf( commands, the invT( command does not have a closed-form formula. However, it can be expressed in terms of the inverse incomplete beta function.
For one degree of freedom, invT( is expressible in terms of simpler functions:
(1) \(\begin{align} \texttt{invT}(p,1)=\tan\left(\pi\left(p-\frac1{2}\right)\right) \end{align}\)
Related Commands
Source: parts of this page were written by the following TI|BD contributors: DarkerLine, GoVegan, jonbush, kg583, Thom M, thornahawk.
History
| Calculator | OS Version | Description |
|---|---|---|
| TI-84+ | 2.30 | Added |