06мְƿԲñʼʮ

ڶڡͶʷͶ

ڵҪݣ

һͶʷյĺ壨˽⣩

Ͷĺ壨գ

ͶϷʵļ㣨գ

һͶʷյĺ
1.壺ͶʷָͶʻֲܵȷصĹͬӰ죬ʹʵͶʳֲͬĿԡ
2.ͶʷղԭͶʷõIJȷԣͶIJȷԣг仯µĹպʷգηպȻֺԼΪͶʾʧȶ档


ͶϷʵļ
һͶϵ
ͶϵʾͶϵĸͶĿʵļȨƽȨڸͶĿͶܶռı乫ʽΪ
P84 [5-1]Ͷϵʵļ
ijҵֱͶAʲBʲУͶAʲΪ8%ƻͶʶΪ500ԪͶBʲΪ12%ƻͶʶΪ500Ԫ
Ҫ󣺼Ͷϵʡ
⣺֪ijҵABʲͶʸռ50%ͶʵʵļȨƽ֮;Ͷʡ
Ͷ=8%×50%+12%×50%=10%
ʲɵͶϵķ
1.Э
ЭһڲͶijһͶĿһͶĿյͳָꡣ㹫ʽΪ
ۣP185
ЭĽֵҲǸֱֵʾͶĿ֮ʱ䶯ķЭΪֵʱʾʲʳͬ䶯ЭΪֵʱʾʲʳʷ䶯ЭֵԽ󣬱ʾʲͶʹϵԽУЭֵԽСʾʲͶʹϵԽԶ
2.ϵ
ϵЭͶʷͶʱ׼֮ıֵ㹫ʽΪ
ֵԣϵֵĴСЭĴСͬ仯ϵ-1+1֮ķΧڱ䶯-1ȫأ+1ȫأ0ʾء
3.ʲɵͶϵܷ
ʲ϶ɵͶʷļ㹫ʽΪ
Vp=W2121+W2222+2W1W2CovR1R2
ʲ϶ɵͶʵı׼ļ㹫ʽΪ
ʽ䷽
a+b2=a2+b2+2ab
Ϸ=a2+b2+2ab
a=Aʲı×aʲı׼
b=Bʲı×Bʲı׼
P186 [5-2]ʲɵͶϵķ
԰5-1ϡٶͶABʲʵı׼Ϊ9%
Ҫ󣺷ֱ㵱ABʲϵֱΪ+1+0.4+0.10-0.1-0.4-1ʱͶʵЭͱ׼