单选题 Find the mean and the mean absolute deviation (MAD) of a series of stock market returns.
【正确答案】 B
【答案解析】(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%.