the Student probability density function for value x using the integer parameter Nu (degrees of freedom). Parameter Nu must be positive integer number, otherwise the result is NAN.

The Student probability density function is defined by the following equation: 

The Student (or T) distribution describes family of curves that depend on a single parameter Nu (degrees of freedom). If a random variable follows a Student distribution, then it must be written as a ratio of a standard normal random variable to the square root of an independent chi-squared random variable, divided by its degrees of freedom. As Nu goes towards infinity, the Student distribution approaches the standard normal distribution.

StudentCDF, StudentCDFInv

StudentPDF Method