Chi2, Gamma, exponential, and maybe beta, erlang and fisher-snedecor pdf, cdf and invcdf functions on toolbox.

[Touns38]

Problem you'd like to fix

I can't calculate chi2 quantile only by going in probability tab and it's unnecessary. I looked for it in the toolbox next to the invnormcdf but it wasnt there :/

Had to open matlab to be faster but i will not be able to do that at the exam.

Describe the solution you'd like

I'd like more usual probability density, cumulative distribution, and inverse cumulative distribution function. It would be useful to manually make chi2 tests on the calc tab and inference tests on density based random variables for example (that's what i'm studying and have an issue with)

Besides, chi2 and fisher distributions were recently added to the probability tab, so it should not be a pain to add them to the toolbox :)