3. Wildlife biologists monitor the ecological health of animals. For large animals whose habitat is hard to access, such as

the Rocky Mountain elk, this can be a problem. Is it possible to reliably estimate the weight of an elk using the elk's

chest girth? Here is a scatterplot showing x = chest girth (cm) and y = weight (kg) for 19 randomly selected Rocky

Mountain elk, along with additional computer output for a least-squares regression line. The mean weight for these elk

is 231 kg. (Context and data from Statistics, Learning from Data.)

(a) Describe the relationship shown in the scatterplot.

(b) Interpret the slope.

(c) Calculate and interpret the residual for the elk with a chest girth of 131 cm and a weight of 211 kg.

(d) Interpret the value of s.

(e) Interpret r2 in context.

Term Coef SE Coef T-Value P-Value

Constant -135.51 35.75 -3.79 0.001

Girth 2.8063 0.2686 10.45 0.000

S = 23.6626 R-sq = 86.5% R-sq(adj) = 85.7%

(f) Construct and interpret a 95% confidence interval for the true slope in this context.

(g) Based only on the confidence interval from part (f), is there convincing evidence of an association between chest

girth and weight for Rocky Mountain elk? Explain.