Weighted Average(continued) Average is per elementary unit o The average of your course grades is your average per course Weighted average is per unit of weight o Your GPa(grade point average) is a weighted average, using credit hours to define the weights. The weighted average is your average per credit hour
Weighted Average (continued) ◆ Average is per elementary unit ⚫ The average of your course grades is your “average per course” ◆ Weighted average is per unit of weight ⚫ Your GPA (grade point average) is a weighted average, using credit hours to define the weights. The weighted average is your “average per credit hour
Example:组合的回报率( Portfolio rate of return) Portfolio expected return(an interest rate, indicating performance)is the weighted average of the expected rates of return of assets in the portfolio, weighted by Dollars invested E(RP=WE(RD+ WE(r,)+.+ WE(R Portfolio contains three stocks. One($1,000 invested)is expected to return 20%o Another($1, 800 invested)expects 15%. Third is $2. 200 and 30% ◆ Total invested is1.000+1.800+2.200=$5.000
Example: 组合的回报率（Portfolio Rate of Return） ◆ Portfolio expected return (an interest rate, indicating performance) is the weighted average of the expected rates of return of assets in the portfolio, weighted by $dollars invested E(RP )=W1E(R1 )+ W2E(R2 )+…+ WnE(Rn ) ◆ Portfolio contains three stocks. One ($1,000 invested) is expected to return 20%. Another ($1,800 invested) expects 15%. Third is $2,200 and 30%. ◆ Total invested is 1,000+1,800+2,200 = $5,000