which of the following regressions represents the strongest linear relationship between x and y? regression…

which of the following regressions represents the strongest linear relationship between x and y? regression 1 y = ax + b a = 2.9 b = -14.5 r = 0.3938 regression 2 y = ax + b a = 8.7 b = -9.4 r = 1.0904 regression 3 y = ax + b a = -3.3 b = -20 r = -0.2546 regression 4 y = ax + b a = 9.6 b = 13.6 r = 0.5311
Answer
Explanation:
Step1: Recall correlation - coefficient concept
The strength of a linear relationship is determined by the absolute - value of the correlation coefficient $r$. The closer $|r|$ is to 1, the stronger the linear relationship.
Step2: Calculate absolute - values of $r$ for each regression
For Regression 1: $|r_1|=|0.3938| = 0.3938$ For Regression 2: $|r_2|=|1.0904|$. But the correlation coefficient $r$ must satisfy $- 1\leq r\leq1$, so this value is invalid. For Regression 3: $|r_3|=|-0.2546| = 0.2546$ For Regression 4: $|r_4|=|0.5311| = 0.5311$
Step3: Compare absolute - values
Since $0.2546<0.3938<0.5311$, Regression 4 has the largest valid $|r|$ value among the valid regressions.
Answer:
Regression 4