问题
单项选择题
Find the mean and the mean absolute deviation (MAD) of a series of stock market returns.（）
A．2%
B．3%
C．4%
答案
参考答案：B
解析：
(14 +20 +24 +22)/4 =20 (mean) Take the absolute value of the differences and divide by n. MAD = [(14-20)+ 20-20)+(24-20)+(22-20)]/4=3%.