out = cars () ¶Speed and Stopping Distances of Cars
Speed of cars and distances taken to stop. Note that the data were recorded in the 1920s.
speedSpeed (mph).
distStopping distance (ft).
Ezekiel, M. (1930). Methods of Correlation Analysis. New York: Wiley.
McNeil, D. R. (1977). Interactive Data Analysis. New York: Wiley.
t = octave.dataset.cars;
# TODO: Add Lowess smoothed lines to the plots
figure;
plot (t.speed, t.dist, "o");
xlabel ("Speed (mph)"); ylabel("Stopping distance (ft)");
title ("cars data");
figure;
loglog (t.speed, t.dist, "o");
xlabel ("Speed (mph)"); ylabel("Stopping distance (ft)");
title ("cars data (logarithmic scales)");
# TODO: Do the linear model plot
# Polynomial regression
figure;
plot (t.speed, t.dist, "o");
xlabel ("Speed (mph)"); ylabel("Stopping distance (ft)");
title ("cars polynomial regressions");
hold on
xlim ([0 25]);
x2 = linspace (0, 25, 200);
for degree = 1:4
[P, S, mu] = polyfit (t.speed, t.dist, degree);
y2 = polyval(P, x2, [], mu);
plot (x2, y2);
endfor