问题
单项选择题
An analyst gathered information about three economic variables. He noted that whenever variable A increased by one unit, variable B increased by 0.2 units but variable C decreased by 0.7 units. The correlation between variables A and B and the correlation between variables A and C, respectively, are closest to: Correlation between variables A and B Correlation between variables A and C（）
A. 1.0 -1.0
B. 1.0 -0.5
C. 0.5 -1.0
答案
参考答案：A
解析：
The relationship between variables A and B is perfect positive correlation (1.0) and the relationship between variables A and C is perfect negative correlation (-1.0).