Two-variable data: Models and scatterplots SAT question

Choice B is correct. The equation representing a linear model can be written in the form $y=a+bx$, or $y=bx+a$, where $b$ is the slope of the graph of the model and $(0,a)$ is the y-intercept of the graph of the model. The scatterplot shows that as the x-values of the data points increase, the y-values of the data points decrease, which means the graph of an appropriate linear model has a negative slope. Therefore, $b<0$. The scatterplot also shows that the data points are close to the y-axis at a positive value of $y$. Therefore, the y-intercept of the graph of an appropriate linear model has a positive y-coordinate, which means $a>0$. Of the given choices, only choice B, $y=-1.9x+10.1$, has a negative value for $b$, the slope, and a positive value for $a$, the y-coordinate of the y-intercept. 

Choice A is incorrect. The graph of this model has a y-intercept with a negative y-coordinate, not a positive y-coordinate.

Choice C is incorrect. The graph of this model has a positive slope, not a negative slope, and a y-intercept with a negative y-coordinate, not a positive y-coordinate.

Choice D is incorrect. The graph of this model has a positive slope, not a negative slope.