stand_t_dens
calculates the density of the univariate t distribution with zero mean and unit variance,
described, for example, in Virolainen (2025).
stand_t_dens(y, nu)
Returns a numeric vector of the same length as y
containing the density values.
a numeric vector containing the values at which the density is to be evaluated.
the degrees of freedom parameter value, a numeric scalar strictly larger than two.
See Virolainen (2025) and the references therein, for example, for the details of the density function of t-distribution with zero mean and unit variance (assume the skewness parameter value is zero to obtain the non-skewed version of the t-distribution).
Virolainen S. 2025. Identification by non-Gaussianity in structural threshold and smooth transition vector autoregressive models. Unpublished working paper, available as arXiv:2404.19707.