1v.normal(1)                   Grass User's Manual                  v.normal(1)
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NAME

6       v.normal  - Tests for normality for vector points.
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KEYWORDS

9       vector, statistics, points, point pattern
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SYNOPSIS

12       v.normal
13       v.normal --help
14       v.normal  [-rl]  map=name  [layer=string]  tests=range[,range,...] col‐
15       umn=name  [--help]  [--verbose]  [--quiet]  [--ui]
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17   Flags:
18       -r
19           Use only points in current region
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21       -l
22           Lognormality instead of normality
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24       --help
25           Print usage summary
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27       --verbose
28           Verbose module output
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30       --quiet
31           Quiet module output
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33       --ui
34           Force launching GUI dialog
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36   Parameters:
37       map=name [required]
38           Name of vector map
39           Or data source for direct OGR access
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41       layer=string
42           Layer number or name
43           Vector features can have category values in different layers.  This
44           number  determines  which  layer  to use. When used with direct OGR
45           access this is the layer name.
46           Default: 1
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48       tests=range[,range,...] [required]
49           Lists of tests (1-15)
50           E.g. 1,3-8,13
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52       column=name [required]
53           Name of attribute column
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DESCRIPTION

56       v.normal computes tests of normality on vector points.
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NOTES

59       The tests that v.normal performs are indexed below.  The tests that are
60       performed  are specified by giving an index, ranges of indices, or mul‐
61       tiple thereof.
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63       1      Sample skewness and kurtosis
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65       2      Geary’s a-statistic and an approximate normal transformation
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67       3      Extreme normal deviates
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69       4      D’Agostino’s D-statistic
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71       5      Modified Kuiper V-statistic
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73       6      Modified Watson U^2-statistic
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75       7      Durbin’s Exact Test (modified Kolmogorov)
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77       8      Modified Anderson-Darling statistic
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79       9      Modified Cramer-Von Mises W^2-statistic
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81       10     Kolmogorov-Smirnov D-statistic (modified for normality testing)
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83       11     Chi-Square test statistic (equal probability  classes)  and  the
84              number of degrees of freedom
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86       12     Shapiro-Wilk W Test
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88       13     Weisberg-Binghams W’’ (similar to Shapiro-Francia’s W’)
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90       14     Royston’s extension of W for large samples
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92       15     Kotz Separate-Families Test for Lognormality vs. Normality
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EXAMPLE

95       Compute  the  sample  skewness and kurtosis, Geary’s a-statistic and an
96       approximate normal transformation, extreme normal deviates,  and  Roys‐
97       ton’s W for the random vector points:
98       g.region raster=elevation -p
99       v.random random n=200
100       v.db.addtable random column="elev double precision"
101       v.what.rast random rast=elevation column=elev
102       v.normal random tests=1-3,14 column=elev
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SEE ALSO

105        v.univar
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AUTHOR

108       James Darrell McCauley <darrell@mccauley-usa.com>,
109       when he was at: Agricultural Engineering Purdue University
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111       Last changed: $Date: 2016-11-14 00:05:32 +0100 (Mon, 14 Nov 2016) $
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SOURCE CODE

114       Available at: v.normal source code (history)
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116       Main  index  | Vector index | Topics index | Keywords index | Graphical
117       index | Full index
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119       © 2003-2019 GRASS Development Team, GRASS GIS 7.6.0 Reference Manual
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123GRASS 7.6.0                                                        v.normal(1)
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