怎样计算朝望收益和标准差 股票BW R R)P)(R-R)2P 15 10 015 00576 03 20 -006 00288 09 40 n036 00000 21 20 n042 00288 33 10 033 00576 1.00 09 07728 5-85-8 怎样计算期望收益和标准差 股票 BW Ri Pi (Ri )(Pi ) (Ri - R ) 2 (Pi ) -.15 .10 -.015 .00576 -.03 .20 -.006 .00288 .09 .40 .036 .00000 .21 .20 .042 .00288 .33 .10 .033 .00576 和 1.00 .090 .01728