statistics math

6. [-/6.25 Points] DETAILS BBBASICSTATSACC 4.2.008.5. MY NOTES ASK YOUR TEACHER You are the foreman of the Bar-S cattle ranch in Colorado. A neighboring ranch has calves for sale, and you are going to buy some calves to add to the Bar-S herd. How much should a healthy calf weigh? Let x be the age of the calf (in weeks), and let y be the weight of the calf (in kilograms). y 39 47 Complete parts (a) through (e), given Ex = 95, Zy = 609, Er?= 2375, Ey? = 81,559, Exy = 13.777, andr = 0.997. (a) Make a scatter diagram of the data. (Select the correct graph.) CHOICE & 200 150 100 so O 10 20 30 40 HONCE D 200 150 100 8 10 20 30 40 CHOICE 200 150 100 so 20 30 CHOICE D 200 150 100 so O 10 (b) Verify the given sums Ex, Ey, Ex?, Eye, Exy, and the value of the sample correlation coefficient r. (For each answer, enter a number. Round your value for / to three decimal places.) Ex = Ey = Ex2 - Exy= (c) Find x, and y. Then find the equation of the least-squares line y = a + b x. (For each answer, enter a number. Round your answers for x and y to two decimal places. Round your answers for a and b to three decimal places.) (d) Graph the least-squares line. Be sure to plot the point (x, y) as a point on the line. (Select the correct graph.) CHOICE A 200 150 O 10 20 30 CHOICE S O 10 20 30 40 CHOICE C 8 8 5 8 O 10 20 30 40 CHOICE D 150 100 O 10 30 (e) Find the value of the coefficient of determination . What percentage of the variation in y can be explained by the corresponding variation in x and the least-squares line? What percentage is unexplained? (For each answer, enter a number. Round your answer for / to three decimal places. Round your answers for the percentages to one decimal place.) explained = unexplained = (1) The calves you want to buy are 13 weeks old. What does the least-squares line predict for a healthy weight (in kg)? (Enter a number. Round your answer to two decimal places.)