Question

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).

x	1	2	10	16	26	36
y	42	46	75	100	150	200

given Σx = 91, Σy = 613, Σx² = 2333, Σy² = 82,005, Σxy = 13,584, and r ≈ 0.998.

Find x, and y. Then find the equation of the least-squares line  = a + bx. (Round your answers for x and y to two decimal places. Round your answers for a and b to three decimal plac

=

+ ?? x

Find the value of the coefficient of determination r². 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? (Round your answer for r² to three decimal places. Round your answers for the percentages to one decimal place.)

r2 =
explained	? %
unexplained	? %

(f) The calves you want to buy are 16 weeks old. What does the least-squares line predict for a healthy weight? (Round your answer to two decimal places.)
? kg

Answer 1