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stats/
sixplot.pro
topsixplot
Statistics
sixplot, x, y [, COLORNAME=COLORNAME] [, BACKNAME=BACKNAME] [, _EXTRA=_EXTRA]
Produce a 6plot as defined in the NIST engineering statistics handbook http://www.itl.nist.gov/div898/handbook/eda/section3/6plot.htm The 6-plot is a collection of 6 specific graphical techniques whose purpose is to assess the validity of a Y versus X fit. The fit can be a linear fit, a non-linear fit, a LOWESS (locally weighted least squares) fit, a spline fit, or any other fit utilizing a single independent variable. The 6 plots are: 1. Scatter plot of the response and predicted values versus the independent variable; 2. Scatter plot of the residuals versus the independent variable; 3. Scatter plot of the residuals versus the predicted values; 4. Lag plot of the residuals; 5. Histogram of the residuals; 6. Normal probability plot of the residuals.
Residuals are calculated using regress()
Parameters
- x in required
X-values to use for 6plot
- y in required
Y-values to use for 6plot
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)
IDL> sixplot, x, y
Statistics
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File attributes
| Modifcation date: | Wed Feb 13 15:47:18 2008 |
| Lines: | 124 |