4

A data set has a correlation coefficient of r = −0.9, with the means of marginal distributions of media de X. = 1 and media de = 2. It is known that one of the following four equations corresponds to the regression of y on x:

Select the correct line.

y = −x + 2 3x − y = 1 2x + y = y = x + 1


Since the linear correlation coefficient is negative, the slope of the line will also be negative, thus ruling out the 2nd and 4th options.

A point on the line is (media de X., media de), that is to say, (1, 2).

2 ≠ −1 + 2

2 · 1 + 2 = 4

The correct line is: 2x + y = 4.