A firm has recorded data on each of their salespeople. Variables recorded include Sales, Age, and Years of Experience. The following output is for a model where sales is predicted using both Age and years of Experience. The plot shows a confidence ellipse for the coefficients of the Experience and Age terms in the model.

Call:

lm(formula = Sales ~ Exper + Age, data = dat)

Residuals:

Min 1Q Median 3Q Max

-19.6295 -8.5655 -0.2572 7.0859 30.7901

Coefficients:

Estimate Std. Error t value Pr(>|t|)

(Intercept) 123.7950 11.8548 10.443 7.77e-14 ***

Exper 1.3053 0.5744 2.273 0.0277 *

Age -1.5173 0.6247 -2.429 0.0190 *

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Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Residual standard error: 11.11 on 47 degrees of freedom

Multiple R-squared: 0.1129,Adjusted R-squared: 0.07516

F-statistic: 2.991 on 2 and 47 DF, p-value: 0.05988

0.0 -1.0 Age coefficient -2.0 -3.0 0.0 0.5 1.0 1.5 2.0 2.5 Exper coefficient