Page 356 - Applied Statistics with R

356 CHAPTER 14. TRANSFORMATIONS

## poly(x, degree = 4)1 -2.0539 2.7940 -0.735 0.463
## poly(x, degree = 4)2 -49.3448 2.7940 -17.661 < 2e-16 ***
## poly(x, degree = 4)3 0.6699 2.7940 0.240 0.811
## poly(x, degree = 4)4 20.5198 2.7940 7.344 3.06e-12 ***
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Residual standard error: 2.794 on 245 degrees of freedom
## Multiple R-squared: 0.5993, Adjusted R-squared: 0.5928
## F-statistic: 91.61 on 4 and 245 DF, p-value: < 2.2e-16

summary(fit_4c)

##
## Call:
## lm(formula = y ~ x + I(x^2) + I(x^3) + I(x^4), data = data_higher)
##
## Residuals:
## Min 1Q Median 3Q Max
## -7.6982 -2.0334 0.0042 1.9532 7.4626
##
## Coefficients:
## Estimate Std. Error t value Pr(>|t|)
## (Intercept) 2.9996 0.3315 9.048 < 2e-16 ***
## x -0.3880 0.3828 -1.014 0.312
## I(x^2) -6.1511 0.5049 -12.183 < 2e-16 ***
## I(x^3) 0.1269 0.1456 0.871 0.384
## I(x^4) 1.0282 0.1400 7.344 3.06e-12 ***
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Residual standard error: 2.794 on 245 degrees of freedom
## Multiple R-squared: 0.5993, Adjusted R-squared: 0.5928
## F-statistic: 91.61 on 4 and 245 DF, p-value: < 2.2e-16

14.2.6 Inhibit Function

coef(lm(y ~ x + x ^ 2, data = quad_data))

## (Intercept) x
## -18.32715 24.87163