12(2)=%42+B22+4+1+B2 R =/2,分 2)/d+1+P2+ P t+1 =B1+1.B+
几何平均与算术平均 Example: suppose in year 1 you earn a return of 10% and the next year a return of 20% e What is your average annual return Because of compounding, it is NOT 15% o we want a number r so that (1+7)(1+7)=(1+7t+1)(1+7t+2) (1+7t+1)(1+ 1 √1.1×1.2 14.9% r is the geometric average of 10 and 20, as opposed to the arithmetic average which is 15
几何平均与算术平均
geonetric average is always Less than the aritl netic average (we are being conservative Is it better to use geometric or arithinetic average (It depends) Can get large differences in averages ex: 5 years of returns on Dell Dell 199O 209 1991 35% L992 25% 1993 410% l995 10% Arithmetic Geometric.5% (can be more of a problem over long horizons)
2.证券投资的风险 风险是指未来的不确定性 没有风险就没有股市 2001年下半年以来的中国股市 2001年9.11 1987年10月19日,被称为“黑色星期一” DJIA下跌了22.6%(508点)
2. 证券投资的风险 ◼ 风险是指未来的不确定性 ◼ 没有风险就没有股市 ◼ 2001年下半年以来的中国股市 ◼ 2001年9.11 ◼ 1987年10月19日，被称为“黑色星期一” DJIA 下跌了22.6%(508点）
近八年中国股市 CHINA SHANGHAI COMPOSITE INDEX s of 1-Mar-2005 2500 2000 1500 1000 Copyright 2005 Yahoo! Inc http://finance.yahoo.com
近八年中国股市