Question

Assume you have collected data pairs (x, y) on a certain variety of tree. x is the number of weeks since the tree was planted and y is the height of the tree in inches. A plot of the data points with the best-fit line is given below. What is the numerical value of the height as predicted by the best-fit line for an age of 40 weeks?

Answer 1

52 1/2 inches. Draw a vertical line up from the 20 week marker and where that line intersects the slanted red line and. Then take a straight edge and draw a line parallel to the "week" line on the bottom of the graph from the intersection to intersect the height line. Where the second line crosses the height line that number is the height of the plant at 20 weeks.