.
.
(, -). . x1, 2, , n.
(variable) - , . , .
: , , , , , , , .
- , , . ( ).
- , , , 10, 100, 1000 . . .
.
( , ) , n ( ). (1),..., X(N), :
` =
, 0. :
(` - 1) + (` - 2) +... + (` - n) =0
() - , , .
( variance) . 1918 . :
s2 =
` ,
N .
. 0 , .
, ( standard deviation) . , .
. , . , , , . , , , .
|
|
N. . N , , , (N+1)/2 . , : 10, 17, 21, 24, 25 21 , (N+1)/2=(5+1)/2=3.
, , , N/2 N/2+1 . , : 5, 5, 6, 7, 8, 8, 9, 9 7,5 (7+8)/2=7,5 , (N/2=8/2=4 N/2+1=4+1=5).
, ( ) ( ).
, ( ), , . 25%, , 25% . 75%, , 75% . , , - 4 . ¼ , ¼ - , ¼ - , ¼ - .
( , ), , , ., , . (: 2, 6, 6, 8, 9, 9, 9, 10 = 9).
, , ( ).
, . , :
. , .
.
:
, , . . =0, =0.