-, , , .
I , , ,) , , , 0,40 (40%), 0,40. I (α) (level of significance).
(level of significance)
.
, . , .
II ( II error) , , , , . II , , , , , , 0,40, 0,40. II β. α, , β (, ). I (α) II (β) . 15.4. (1 β) II .
. 15.4. I () II (/3)
II (Type I error)
-, , , .
(power of a test) (1 β) , . β , α. α (, 0,001) β. . α 0,05; 0,01; α . α, , β . α β , . β, .
(power of a test)
, .
4.
, I II , . . 30 Internet 17 , Internet. , Internet
= 17/30 = 0,567.
σp :
z :