Counting observation variance from list elements
Source: PROLOG str. 198 Wydawnictwo PLJ Warszawa 1991 ISBN 83-85190-63-5
Program source code: variance.pl
wari(L, W) :- sred(L, Sr), rozn2(L, H, Sr), suma(H, Suma, 0, Ilosc, 0), W is Suma/Ilosc. rozn2([], [], _). rozn2([H|T], [R|T1], Sr) :- R is (H - Sr)*(H - Sr), rozn2(T, T1, Sr). test :- wari([1, 2, 3, 4, 5]).