fixed problem with doc string
fixed problem with doc string

when we switched over to the scipy one-way ANOVA this doc test p-value started
coming back as nan. it turned out that this was right, because there was no
within-group variance in the groups being compared and our ANOVA wasn't
handling that correctly. this is an example of why we should make a concerted
effort to use scipy when possible for our stats.

Kleptobismol/scikit-bio,SamStudio8/scikit-bio,SamStudio8/scikit-bio,wdwvt1/scikit-bio,Kleptobismol/scikit-bio,jensreeder/scikit-bio,wdwvt1/scikit-bio,Achuth17/scikit-bio,averagehat/scikit-bio,colinbrislawn/scikit-bio,demis001/scikit-bio,jdrudolph/scikit-bio,gregcaporaso/scikit-bio,colinbrislawn/scikit-bio,jairideout/scikit-bio,demis001/scikit-bio,corburn/scikit-bio,johnchase/scikit-bio,jairideout/scikit-bio,xguse/scikit-bio,gregcaporaso/scikit-bio,kdmurray91/scikit-bio,jensreeder/scikit-bio,averagehat/scikit-bio,johnchase/scikit-bio,Kleptobismol/scikit-bio,anderspitman/scikit-bio,xguse/scikit-bio,corburn/scikit-bio,jdrudolph/scikit-bio,anderspitman/scikit-bio,kdmurray91/scikit-bio,Achuth17/scikit-bio