题目
The result of the linear regression is: Y=0.10-0.50X, with a correlation coefficient ρ=-0.90. The fraction of the variance of Y attributable to X is equal to:
选项
A.-0.90
B.+0.90
C.+0.81
D.-0.50
答案
C
解析
R-squared equals the square of the correlation coefficient and measures the fraction of the variance of Y that is attributable to X. R2=ρ2=(-0.90)2=0.81R平方等于相关系数的平方，并测量可归因于X的Y的方差的分数。R2=ρ2=(-0.90)2=0.81