SCATTERGRAPHS Plot the points Draw in the line of best fit Select two points which lie on the line Find the gradient Hence find the equation of the line

x 2 3 4 5 6 7 8 y 10 11 14 15 17 x y Plot the points

x 2 3 4 5 6 7 8 y 10 11 14 15 17 x y Draw the line of best fit

x 2 3 4 5 6 7 8 y 10 11 14 15 17 Select two points on the line m = y2 – y1 x2 – x1 Find the gradient m = y2 – y1 = 15 – 10 x2 – x1 7 - 2 m = 1

x 2 3 4 5 6 7 8 y 10 11 14 15 17 Find the equation of the line y = mx + c y = 1×x + c But (7,15) lies on the line So 15 = 1×7 + c And c = 8 Equation of line is y = x + 8

SCATTERGRAPHS Plot the points Draw in the line of best fit Select two points which lie on the line Find the gradient Hence find the equation of the line

x 50 52 55 56 58 61 62 y 20 19 18 17 15 x y Plot the points

x 50 52 55 56 58 61 62 y 20 19 18 17 15 Draw in the line of best fit y

x 50 52 55 56 58 61 62 y 20 19 18 17 15 Select two points on the line m = y2 – y1 x2 – x1 Find the gradient m = y2 – y1 = 18 – 17 x2 – x1 56 - 58 m = - 1/2

x 50 52 55 56 58 61 62 y 20 19 18 17 15 Find the equation of the line y = mx + c y = -1/2×x + c But (56,18) lies on the line So 18 = -1/2×56 + c And c = 46 Equation of line is y = -1/2x + 46