单选题

An analyst is investigating the distribution of the SMG stock's return over time. He calculated the mode of 12 percent, the mean of 11 percent, and the median of 11.5 percent. The distribution can be best described as（）。

A、 positively skewed, with a long tail on the left side.
B、 negatively skewed, with a long tail on the left side.
C、 positively skewed, with a long tail on the right side.

【正确答案】 B

【答案解析】

For a symmetrical distribution, the mean, median, and mode are equal. For a positively skewed distribution, the mode is less than the median, which is less than the mean. The mean is affected by outliers. In a positively skewed distribution there are large, positive outliers which will tend to “pull” the mean upward. For a negatively skewed distribution, the mean is less than the median, which is less than the mode. In this case, there are large, negative outliers which tend to “pull” the mean downward.