Assignment 3 Model Answers STA1DCT 1. Scatterplot 1: correlation = 0.99 Scatterplot 2: correlation = 0.01 Scatterplot 3: correlation = - 0.5 Scatterplot 4: correlation = 0.9 Scatterplot 5: correlation = 0.6 Scatterplot 6: correlation = - 0.99 2. To find the slope we can use the formula m = (y1 - 2)/(x1 - x2). Therefore the slope for our equation is equal to m = (4 - 6) (7 - 1) _ -2 6 5 =- 3. To find the intercept we simply need to solve y = - 3x+c for c when using either (x = 4, y = 7) or (x = 6, y = 1). Therefore 1 =- 3×6+c=>c=1+18 = 19 and so the intercept is equal to 19. 3. Data set 1 (black points): intercept = 0, slope = 4 Data set 2 (yellow points: intercept = 10, slope = 4 Data set 3 (red points): intercept = 10, slope = 10 Data set 4 (white points): intercept = 0, slope = 0.5 Data set 5 (blue points): intercept = 80, slope = - 4 4. Of course there are many examples. Let's look at number of films Nicholas Cage appeared in versus pool drownings. You can look at this at http://tylervigen. com/view_correlation?id=359. (a) Number of films Nicholas Cage appeared in and number of people who drowned by falling into a swimming pool. (b) i. 24,642. ii. 11,256. iii. 100 x 24642/(24642 + 11256) = 68.64% (c) =CORREL (A2: A12, B2 : B12) gives the correct answer of 0.666004. (d) An example plot is below. 4.5 4 3.5 3 2.5 Number of Nicholas Cage films 2 1.5 1 0.5 0 80 90 100 110 Number of drownings 120 130