k
"
mk = E(Xk) = xkdF (x)
-"
mk = E(Xk) = xkpi
i
i
"
mk = E(Xk) = xkf(x)dx
-"
k
µk = E(X - E(X))k
µk = E(X - E(X))k = (xi - E(X))kpi
i
"
µk = E(X - E(X))k = (x - E(X))kf(x)dx
-"
m1
E(X) = m1 = xipi
i
"
E(X) = m1 = xf(x)dx
-"
X - E(X) X
E(X)
" E(a · X + b) = a · E(X) + b a b
" E(X + Y ) = E(X) + E(Y )
" E(X - Y ) = E(X) - E(Y )
" E(X · Y ) = E(X) · E(Y ) X Y
 µ2
V (X) D2(X) Ã2
V (X) = µ2 = E(X - E(X))2 = (xi - E(X))2pi
i
"
V (X) = µ2 = E(X - E(X))2 = (x - E(X))2f(x)dx
-"
" V (a · X + b) = a2 · V (X) a b
" V (X + Y ) = V (X) + V (Y ) X Y
" V (X - Y ) = V (X) + V (Y ) X Y
" V (X) = E(X2) - (E(X))2 = m2 - m2
1
à D(X)
à = D(X) = V (X)
 Å‚
µ3
Å‚ =
Ã3
K
µ4
K = - 3
Ã4
-3
p 0 d" p d" 1 X
kp
P (X d" kp) e" p P (X e" kp) e" 1 - p
kp X
kp p
kp
1 - p
"
"
"
"
"
"
1
me /2
1
F (me) d" /2 d" F (m+)
e
me
1
f(x)dx = /2
-"
xmax
xmin
R = xmax - xmin