Bighorn sheep are beautiful wild animals found throughout the western United States. Data for this problem are based on information taken from The Desert Bighorn, edited by Monson and Sumner (University of Arizona Press). Let x be the age of a bighorn sheep (in years), and let y be the mortality rate (percent that die) for this age group. For example, x = 1, y = 14 means that 14% of the bighorn sheep between 1 and 2 years old die. A random sample of Arizona bighorn sheep gave the following information:

Σx = 15; Σy = 86.9; Σx² = 55; Σy² = 1544.73; Σxy = 273.4

(a) Draw a scatter diagram.

(b) Find the equation of the least-squares line.

(c) Find r. Find the coef­ficient of determination r². Explain what these measures mean in the context of the problem.

(d) Test the claim that the population correlation coef­ficient is positive at the 1% level of signifi­cance.

(e) Given the lack of signi­ficance of r, is it practical to fi­nd estimates of y for a given x value based on the least-squares line model? Explain.

Transcribed Image Text:

2 14 18.9 14.419.6 20.0