A graph shows the survey results for a group of students who were asked how many honors classes they have taken and how many elective classes: A scatter plot is shown with the title class choices. The x axis is labeled number of honors classes and the y axis is labeled number of electives. Data points are located at 1 and 8, 3 and 6, 3 and 9, 5 and 3, 6 and 6, 6 and 9, 8 and 6. A line of best fit crosses the y axis at 9 and passes through the point 6 and 6. How many elective classes would students likely have taken if they have taken 12 honors classes? 15, because y = one halfx + 9 12, because y = y = negative one halfx + 9 6, y = ˜one halfx + 9 3, because y = negative one halfx + 9
Accepted Solution
A:
The first thing to do in this case is to find the equation of the line that represents the problem. You have two points given: (0, 9) (6, 6) The generic equation is: y-yo = m (x-xo) Where; m = (y2-y1) / (x2-x1) m = (6-9) / (6-0) m = -3 / 6 m = -1 / 2 We choose any point: (xo, yo) = (0, 9) We rewrite: y-yo = m (x-xo) y-9 = (- 1/2) (x-0) y = -1 / 2x + 9 So we have that for x = 12 y = -1 / 2 (12) +9 y = -6 + 9 y = 3 answer: 3, because y = negative one halfx + 9