NO.PZ2015120604000051
问题如下:
The table below shows part of the monthly stock returns of Ivy Corp.
Calculate the sample variance for Ivy Corp. returns, assuming above table inclues all samples.
选项:
A.8.78%.
B.64.2%2.
C.77.1%2.
解释:
C is correct
= [(20 - 7.7)2 + (4 - 7.7)2 + (-5- 7.7)2 + (12- 7.7)2 + (3 - 7.7)2 + (12- 7.7)2] / (6-1) = 77.1%2
第一步,7.7是从这些里面求出的算术平均数吗?