Explanation for Question 12 From the Math (Calc) Section on the 2019 October Sat
Now in number 12, we're asked which of the following could be an equation 2 for the line of best fit of this scatterplot shown above. 3 So for talking about a line of best fit, 4 what that means is that we can draw a line on this graph to 5 show a line that's pretty similar. It's very close to all the points, 6 although it might not connect them. All right. 7 And these points are really close together. So a line of best fit might 8 look something like this. Right. See how it's kind of on some of the 9 points, maybe a little above, maybe a little below. 10 And so if we want to find an equation for this line of best 11 fit, the first thing we can do as, 12 um, is looking at what our slope would be, 13 right? Our slope is going to be positive so we can eliminate any answer 14 choices that have a negative slope, which in this case are C and D. 15 And so now probably the best thing to do is to think about the 16 slope of this line a little bit further, 17 um, more so with the numbers, right? Are we going up by 0.8? 18 Every time we go over one, or are we going up by three? 19 Every time we go over one. And so we can pick a couple of 20 points that this line seems to go through to figure out what our slope 21 would be as an estimate. It might not be perfect, 22 but it should hopefully be close to one of the two numbers that were 23 given. And so we can pick this point, 24 which appears to be three comma 10, 25 and then maybe we can also pick this point up here, 26 right? Which appe...