1. a) A student obtained a mark of 75 on an English exam, but was absent for the Humanities exam. Justify using the data and the regression line equation from below to predict the grade he would obtain on the Humanities exam, and find his exam grade. The following table show the percentages of 10 students in English and Humanities exams: English 92 Hums 100 42 188 80 80 88 100 90 f1(x) 0.528x + 38.7 80 70 60 (eng,hum) 50 40 30 20 10 0 10 20 30 40 50 60 70 80 90 100 y 20 30 80 60 54 46 40 54 54 60 66 80 68 62 54 There is a moderate positive correlation between the exam results. (Regression Line) b) If another student was absent for the English exam, and his grade on the English exam was 20, state with reason whether it is justifiable to predict his English grade using the regression equation. b) a) Increasing 2. Consider the following scatter plots and suggest explanations for the form, strength and association. Increasing Grade in Maths vs grade in Art Increasing Height vs shoe size Increasing Increasing c) Increasing Amount of revision vs score in test Increasing Gas mileage VS weight of car Increasing d) Increasing Increasing e) Temperature vs heating bill 3. You conduct a series of timed experiments on 10 members of a gym in two circuit training events and record the following information. a) 20 squat jumps b) 20 pull ups c) weight d) height The results are shown below. 1 2 3 4 a (seconds) 43 52 34 53 b [seconds) 44 49 c [kg) 68 63 d (m) 1.64 33 50 45 56 73 63 1.50 1.67 1.75 6 7 8 34 57 36 61 50 75 57 1.45 1.35 1.87 1.67 S| 8 10 34 67 33 77 55 1.56 1.70 Draw separate scatter diagrams to represent the following information: a) height vs weight b) weight vs squat jumps c) squat jumps vs pull ups. Comment on the direction, association, form and strength of the correlation. i) Draw a line of best fit on each of the scatter diagrams. Use the line of best fit to estimate the weight of a person measuring 1.68 m. ii) iii) Use the line of best fit to estimate the time taken for a person to do 20 squat jumps given that they took 45 seconds to do 20 pull ups. iv) Determine which graphs would give the most accurate predictions.