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NAME
v.normal - Tests for normality for points.
KEYWORDS
vector, statistics
SYNOPSIS
v.normal
v.normal help
v.normal [-rql] map=string tests=range[,range,...] column=string [--verbose] [--quiet]
Flags:
- -r
- Use only points in current region
- -q
- Quiet
- -l
- lognormal
- --verbose
- Verbose module output
- --quiet
- Quiet module output
Parameters:
- map=string
- point vector defining sample points
- tests=range[,range,...]
- Lists of tests (1-15): e.g. 1,3-8,13
- column=string
- Attribute column
DESCRIPTION
v.normal
computes tests of normality on vector points.
NOTES
The tests that v.normal performs are indexed
below. The tests that are performed are specified by
giving an index, ranges of indices, or multiple thereof.
- Sample skewness and kurtosis
- Geary's a-statistic and an approximate normal transformation
- Extreme normal deviates
- D'Agostino's D-statistic
- Modified Kuiper V-statistic
- Modified Watson U^2-statistic
- Durbin's Exact Test (modified Kolmogorov)
- Modified Anderson-Darling statistic
- Modified Cramer-Von Mises W^2-statistic
- Kolmogorov-Smirnov D-statistic (modified for normality testing)
- Chi-Square test statistic (equal probability classes) and
the number of degrees of freedom
- Shapiro-Wilk W Test
- Weisberg-Binghams W'' (similar to Shapiro-Francia's W')
- Royston's extension of W for large samples
- Kotz Separate-Families Test for Lognormality vs. Normality
EXAMPLE
v.random random n=200
v.db.addtable random col="elev double precision"
v.what.rast random rast=elevation.10m col=elev
v.normal random tests=1-3,14 col=elev
computes the sample skewness and kurtosis, Geary's
a-statistic and an approximate normal transformation,
extreme normal deviates, and Royston's W for the
random vector points.
SEE ALSO
v.univar
AUTHOR
James Darrell McCauley
<darrell@mccauley-usa.com>,
when he was at:
Agricultural
Engineering
Purdue University
Last changed: $Date: 2007-03-19 22:18:19 -0800 (Mon, 19 Mar 2007) $
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