Statistics Worksheets

Elementary Statistics Name: Study Guide 9 Class: Due Date: Score: No Work ⇔ No Points Use Pencil Only ⇔ Be Neat & Organized 1. Suppose working with a set of 5 ordered–pairs, we gathered the following: ∑ x = 20, ∑ x 2 = 90, ∑ y = 44, ∑ y 2 = 430, ∑ xy = 195 (a) (4 points) Find the value of linear correlation coefficient. Round to three decimal places. (a) (b) (2 points) Find the value of coefficient of determination. Round to the near- est whole percent. (b) (c) (4 points) Find the equation of the regression line. (c) (d) (2 points) Predict y value if x = 4.5 assuming the linear correlation is not significant. (d) Page 1 of 4 Study Guide 9 Total Points: 50 2. Study time in hours and quiz result of 5 randomly selected students are given below in the form of ordered–pairs (Study Time, Quiz Result): (3, 14), (2, 17), (1, 20), (4, 12), (5, 10) (a) (3 points) Complete the table below using the data given: x y x 2 y 2 x · y ∑ x = ∑ y = ∑ x 2 = ∑ y 2 = ∑ xy = (b) (2 points) Find the value of linear correlation coefficient. Round to three decimal places. (b) (c) (2 points) Find the equation of the regression line. (c) (d) (3 points) Predict the quiz result for someone who studied 2.5 hours assum- ing the linear correlation is significant. Round your final answer to a whole number. (d) Page 2 of 4 Study Guide 9 Total Points: 50 3. Consider the following points below: (2, 4), (6, 8), (6, 10), (2, 6), (4, 4), (10, 8), (8, 12), (6, 4), (14, 8), (16, 12), (18, 10), (14, 10), (20, 20) (a) (2 points) Find the value of the coefficient of determination r 2 to the nearest percentage. (a) (b) (2 points) Find the equation of the regression line. (b) (c) (3 points) Assuming linear correlation is significant, predict the y value for x = 10. (c) (d) (3 points) Plot each point and draw the regression line below. 0 2 4 6 8 10 12 14 16 18 20 0 2 4 6 8 10 12 14 16 18 20 4. The midterm exam score and the overall grade for a random sample of 12 students in an elementary statistics course are shown in the following table. Midterm Grade Score 50 90 70 80 60 90 90 80 70 70 60 50 Overall Grade 65 80 75 75 45 95 85 80 65 70 65 55 Table 1: Midterm Scores & Overall Grades Page 3 of 4 Study Guide 9 Total Points: 50 (a) (2 points) Find the value of the correlation coefficient r. (a) (b) (2 points) Find the value of the coefficient of determination r 2 to the nearest percentage and explain what the value means in the case. (b) (c) (2 points) Find the equation of the regression line. (c) (d) (3 points) Assuming linear correlation is significant, predict the overall grade if the midterm grade is 75. (d) 5. The body weight and the blood sugar level for a random sample of 10 randomly selected adults are shown in the following table. Body Weight 150 190 135 180 145 180 210 145 177 195 Blood Sugar Level 105 125 99 115 125 132 155 100 135 145 (a) (2 points) Find the value of the correlation coefficient r. (a) (b) (2 points) Find the value of the coefficient of determination r 2 to the nearest percentage and explain what the value means in the case. (b) (c) (2 points) Find the equation of the regression line. (c) (d) (3 points) Assuming linear correlation is not significant, predict the blood sugar level for an adult who weighs 160 pounds. (d) Page 4 of 4 Study Guide 9 Total Points: 50