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stats/
fourplot.pro
topfourplot
Statistics
fourplot [, x], y [, COLORNAME=COLORNAME] [, BACKNAME=BACKNAME] [, _EXTRA=_EXTRA]
create a fourplot for Exploratory Data Analysis http://www.itl.nist.gov/div898/handbook/eda/section3/4plot.htm The 4-plot is a collection of 4 specific EDA graphical techniques whose purpose is to test the assumptions that underlie most measurement processes. A 4-plot consists of a 1. run sequence plot; 2. lag plot; 3. histogram; 4. normal probability plot. If the 4 underlying assumptions of a typical measurement process hold, then the above 4 plots will have a characteristic appearance (see the normal random numbers case study below); if any of the underlying assumptions fail to hold, then it will be revealed by an anomalous appearance in one or more of the plots. references Chambers, John, William Cleveland, Beat Kleiner, and Paul Tukey, (1983), Graphical Methods for Data Analysis, Wadsworth.
Residuals are calculated using regress()
Parameters
- x in optional
x-values to use in the 4-plot
- y in required
y-values to use in the 4-plot
Keywords
- COLORNAME in optional
Name of the color to plot with, see fsc_color()
- BACKNAME in optional
Name of the background color, see fsc_color()
- _EXTRA in optional
Extra keywords to plot, oplot, and histoplot
Examples
IDL> x=findgen(101)
IDL> x=x[sort(randomu(seed, 101))]
IDL> y=x+5 + randomn(seed, 101)*10
IDL> fourplot, x, y
Author information
- History:
Mon Sep 8 15:17:11 2008, Brian Larsen made x an optional input and minor plot edits Wed Feb 13 15:12:38 2008, Brian Larsen written and tested
Statistics
| Lines: | 60 |
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File attributes
| Modifcation date: | Mon Sep 22 12:38:48 2008 |
| Lines: | 128 |