@Silverfish: In "t distribution", or "Weibull distribution", "t" & "Weibull" are nouns being used attributively as adjectives. Fair enough, but give some people an inch & they'll take a mile, so we see "t distributed" & "Weibull distributed" - with "t" & "Weibull" as adverbs - now & again. Nevertheless the possessive modifier "Student's" is a strong enough reminder of "t"s true role that to write "Student's t distributed" really needs a brass neck or a tin ear. What about "t-ishly distributed"?