安宝123 · 2020年02月29日

问一道题：NO.PZ201709270100000102

1. CFA II
2. Quantitative

* 问题详情，请 查看题干

问题如下：

2. Based on Exhibit 1, the sample covariance is closest to:

选项：

A.

−9.2430.

B.

−0.1886.

C.

8.4123.

解释：

B is correct.

The sample covariance is calculated as $sum_{i=1}^n{(X_i-\overline{X)}}(Y_i-\overline Y)$/(n-1)=9.2430/49=0.1886

为什么除以自由度 n-1呢？