%mathpiper,def="tDistribution"

/* Guard against distribution objects with senseless parameters
   Anti-nominalism */

tDistribution(m_IsRationalOrNumber)_(Not IsPositiveInteger(m)) <-- Undefined;

%/mathpiper



%mathpiper_docs,name="tDistribution",categories="User Functions;Statistics & Probability"
*CMD tDistribution --- Student's $t$ distribution
*STD
*CALL
	{tDistribution}(m)

*PARMS 
{m} -- integer, number of degrees of freedom

*DESC

*REM what does it do???
The function {tDistribution} returns the ...

Let $Y$ and $Z$ be independent random variables, $Y$ have the 
NormalDistribution(0,1), {Z} have ChiSquareDistribution(m). Then 
$Y/Sqrt(Z/m)$ has tDistribution(m).

Numerical value of {m} must be positive integer.
%/mathpiper_docs