问题
单项选择题
A sample of monthly returns of aggressive growth funds contains 35,20,30,50 and 55. Find out the range, mean absolute deviation, and variance of the data set Mean AbsoluteSample Range DeviationVariance（）
A. 17 11.6 415
B. 17 23.2 207.5
C. 35 11.6 207.5
答案
参考答案：C
解析：
The range is the maximum value- minimum value =55-20=35 Calculate the mean: (35+20+30+50+55)/5=38. To get the mean absolute deviation, sum the deviations around the mean ignoring the sign and then divide by the number of observations=(3+18+8+12+17)/5=11.6. Sample variance =(32+182+82+122+172)/(5-1)=207.5