# MinutePlot validation -- Linear and polynomial regression (cars)
# Install once: nothing -- this script uses base R only

# Versions (compare against those stated on this page):
cat(R.version.string, "\n")

# Load data:
d <- cars                        # built-in; or: d <- read.csv("cars.csv")  (same folder as script)

# Analysis (one print per table shown on the page, in page order):
fit1 <- lm(dist ~ speed, data = d)
print(summary(fit1))                                    # coefficients, SE, t, p, R2, F
fit2 <- lm(dist ~ speed + I(speed^2), data = d)
print(summary(fit2))                                    # quadratic (degree 2)