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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