One, variance law

Variance law is the commonly used method of magnanimity venture capital investment. Regard the income of venture capital investment as a random variable, criterion its variance does not decide with respect to the delegate rate perhaps says venture rate. Variance is to reflect the numerical value of random variable and the deviate degree that its expect to be worth, it is the mathematical expectation that random variable may be worth the deviation square that expects to be worth to its individually.

Set: Random variable is X, its variance is D(x) , criterion:

D(x)=E[x-E(x)]2 (type 1, 1)

In type: E(x) -- the expectation value of random and variable X.

To disperse random variable, the computational formula of its variance is:

In type: PK -- the probability that random and variable X is Xk

XK -- K the likelihood is worth

To successive model random variable, the computational formula of its variance is:

In type: F(x) -- the probability density function of random and variable X.

In applying actually, analyse to facilitate, still introduce the amount that has identical dimension with random variable normally, write down for σ (X) , say differ for standard deviation or mean square.

2, β coefficient and model of price of capital capital fund

Model of price of capital capital fund by American economist W. F. Dr. Sharpe at 20 centuries 60 time metaphase puts forward first, dr. Sharpe waits for achievement of financial terrain of economics in property price distinguished, have the honor to win 1990 Nobel economics award.

Model of price of capital capital fund (CAPM) thinks, in a capital market that develops highly, any investment regard the deed that buys some kind of negotiable securities as, negotiable securities value (case) wave motion is the risk that investor assumes. Total risk can be divided for systematic risk and blame system risk; Effective investment combination can make investor susceptive is not systematic risk for 0; Systematic risk also calls market risk, express by those main influencing factor (can affect all asset value) the risk that change and produces.

CAPM already was used extensively at negotiable securities to invest an analysis, look from the angle of investor, CAPM has the following meaning:

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