data(mtcars)
model <- lm(mpg ~ wt, data = mtcars)
summary(model)
##
## Call:
## lm(formula = mpg ~ wt, data = mtcars)
##
## Residuals:
## Min 1Q Median 3Q Max
## -4.5432 -2.3647 -0.1252 1.4096 6.8727
##
## Coefficients:
## Estimate Std. Error t value Pr(>|t|)
## (Intercept) 37.2851 1.8776 19.858 < 2e-16 ***
## wt -5.3445 0.5591 -9.559 1.29e-10 ***
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Residual standard error: 3.046 on 30 degrees of freedom
## Multiple R-squared: 0.7528, Adjusted R-squared: 0.7446
## F-statistic: 91.38 on 1 and 30 DF, p-value: 1.294e-10
plot(mtcars$wt, mtcars$mpg,
main = "Scatterplot of wt vs mpg",
xlab = "Weight (1000 lbs)",
ylab = "Miles per Gallon (mpg)",
pch = 19, col = "blue")
abline(model, col = "red", lwd = 2)

data(ToothGrowth)
model <- lm(len ~ dose, data = ToothGrowth)
summary(model)
##
## Call:
## lm(formula = len ~ dose, data = ToothGrowth)
##
## Residuals:
## Min 1Q Median 3Q Max
## -8.4496 -2.7406 -0.7452 2.8344 10.1139
##
## Coefficients:
## Estimate Std. Error t value Pr(>|t|)
## (Intercept) 7.4225 1.2601 5.89 2.06e-07 ***
## dose 9.7636 0.9525 10.25 1.23e-14 ***
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Residual standard error: 4.601 on 58 degrees of freedom
## Multiple R-squared: 0.6443, Adjusted R-squared: 0.6382
## F-statistic: 105.1 on 1 and 58 DF, p-value: 1.233e-14
plot(ToothGrowth$dose, ToothGrowth$len,
main = "Scatterplot of dose vs len",
xlab = "Dose",
ylab = "Tooth Length",
pch = 19, col = "blue")
abline(model, col = "red", lwd = 2)
