( ). xn , n , . , ( ) .
, . . (12).
σ(x) (11).
V xn :
. (20)
n ( x) P ( 0,95) z (P.n) .
V < z∙σ (x), x ; V ≥ z∙σ (x), x , . x σ (x) ( n 1.
xi. . , , :
. (21)
xi , , 3σ: 3σ, . :
Q' (P) = t (P,n)∙ , (22)
t .
Q (P) , (5) (6).
∆ () (14 19), σ (x) .