Maxima Function
mean_chi2 (n)
Returns the mean of a Chi-square random variable Chi^2(n), with n>0.
The Chi^2(n) random variable is equivalent to the Gamma(n/2,2), therefore when Maxima has not enough information to get the result, a noun form based on the gamma mean is returned.
(%i1) load (distrib)$ (%i2) mean_chi2(n); n (%o2) mean_gamma(-, 2) 2 (%i3) assume(n>0)$ mean_chi2(n); (%o4) n