What is the consensus way to typeset statistical distributions? For the normal distribution I have seen all of:
$X\sim N(\mu,\,\sigma^{2})$
$X\sim\mathrm{N}(\mu,\,\sigma^{2})$
$X\sim\mathcal{N}(\mu,\,\sigma^{2})$
Are there any subtleties for distributions with multiple letters in their name or which use the Greek alphabet, particularly since the latter are not automatically italic in LaTeX? For instance:
$X\sim Exp(\lambda)$
$X\sim\Gamma(a,\, b)$
(My personal inclination would be for all distribution names to be upright, which is particularly convenient for the Greek-letter distributions. But this does not seem to be the norm in my sources.)
A related question is the degree of spacing which is appropriate between parameters for those distributions, like the normal, which take more than one.
$X\sim\mathit{Exp}(\lambda)$, not$X\sim Exp(\lambda)$. The italic font you get with$Exp$would be correct only if each letter was a separate mathematical symbol (for instance, if they were three variables being multiplied together). Also, I don't know what the convention is, but I think that$X\sim N(\mu,\sigma^{2})$is perfectly readable without any extra space. – MSC Feb 17 '13 at 20:18