单选题
The most recent returns of a fund are as follow:
| Year | Return(%) |
| 2007 | -20.60 |
| 2008 | 15.00 |
| 2009 | 0.50 |
| 2010 | 9.80 |
| 2011 | 4.60 |
The mean absolute deviation of returns for the fund is closest to:
【正确答案】
A
【答案解析】
A is correct. The mean absolute deviation (MAD) for a sample is calculated as follow:
where
Xi is the return of the fund during year i
is the mean of the returns of the sample
n is the number of returns in the sample
i is the index for the year
In this problem: Mean:
＝(–20.60% + 15.00% + 0.50% + 9.80% + 4.60%)/5 = 1.86%
MAD = (|–20.60% – 1.86%| + |15.00% – 1.86%| + |0.50% – 1.86%| + |9.80% – 1.86%| + |4.60%– 1.86%|)/5 = 47.64% / 5=9.53%
