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8.2.45.11 octave.dataset.cars ¶

Static Method: out = cars () ¶

Speed and Stopping Distances of Cars

Description ¶

Speed of cars and distances taken to stop. Note that the data were recorded in the 1920s.

Format ¶

speed

Speed (mph).

dist

Stopping distance (ft).

Source ¶

Ezekiel, M. (1930). Methods of Correlation Analysis. New York: Wiley.

References ¶

McNeil, D. R. (1977). Interactive Data Analysis. New York: Wiley.

Examples ¶

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