Explanation for Question 4 From the Math (Calc) Section on the 2019 March Sat
Question four says the scatterplot above shows eight data points in the X, 2 Y plane. A line of best fit is also shown for the data. 3 If each data point is shifted, three points upward and a new line of 4 best fit, the shifted points of strong. How will the value of the Y 5 intercept of the new line compare with that of the line shown? 6 So let's look at this graph up here. 7 If all of these data points were shifted, 8 three units upward, so with the line of best fit. 9 So I'm just going to estimate that inside that, that happens about here and 10 the line would look, something like that. 11 So all you have to know is if the data points move upward, 12 so do the line of best fit or so does the line of best 13 fit because that's just an approximation of the average of all those data points. 14 So if you notice the lines, 15 Y intercept is still there, 16 it still exists. It's just that for now instead of one. 17 So that means that D is incorrect because it does still have a Y 18 intercept C is incorrect because it didn't stay in the same place. 19 It did move upwards B as wrong because it didn't move down. 20 It moved up. And that's why a is correct because the Y intercepts value 21 went from one to four. So it did increase.