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8.2.45.3 octave.dataset.airquality ¶

Static Method: out = airquality () ¶

New York Air Quality Measurements from 1973

Description ¶

Daily air quality measurements in New York, May to September 1973.

Format ¶

Ozone

Ozone concentration (ppb)

SolarR

Solar R (lang)

Wind

Wind (mph)

Temp

Temperature (degrees F)

Month

Month (1-12)

Day

Day of month (1-31)

Source ¶

New York State Department of Conservation (ozone data) and the National Weather Service (meteorological data).

References ¶

Chambers, J. M., Cleveland, W. S., Kleiner, B. and Tukey, P. A. (1983). Graphical Methods for Data Analysis. Belmont, CA: Wadsworth.

Examples ¶

t = octave.dataset.airquality
# Plot a scatter-plot plus a fitted line, for each combination of measurements
vars = {"Ozone", "SolarR", "Wind", "Temp" "Month", "Day"};
n_vars = numel (vars);
figure;
for i = 1:n_vars
  for j = 1:n_vars
    if i == j
      continue
    endif
    ix_subplot = (n_vars*(j - 1) + i);
    hax = subplot (n_vars, n_vars, ix_subplot);
    var_x = vars{i};
    var_y = vars{j};
    x = t.(var_x);
    y = t.(var_y);
    scatter (hax, x, y, 10);
    # Fit a cubic line to these points
    # TODO: Find out exactly what kind of fitted line R's example is using, and
    # port that.
    hold on
    p = polyfit (x, y, 3);
    x_hat = unique(x);
    p_y = polyval (p, x_hat);
    plot (hax, x_hat, p_y, "r");
  endfor
endfor