Opened 6 years ago
Last modified 11 months ago
#2376 new enhancement
Add p-value for regression slope in r series
Reported by: | mastho | Owned by: | |
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Priority: | normal | Milestone: | 7.6.2 |
Component: | Raster | Version: | svn-releasebranch70 |
Keywords: | r.series, p-value regression | Cc: | pvanbosgeo |
CPU: | Unspecified | Platform: | Unspecified |
Description
The calculation of t-values has been added to r.series in r53742 (method=tvalue). It would be nice to have also the corresponding p-values for the regression as method in r.series.
Also discussed here: http://osgeo-org.1560.x6.nabble.com/Calculate-p-value-for-regression-slope-in-r-series-td5014228.html
Change History (12)
comment:1 Changed 6 years ago by
Keywords: | r.series p-value regression → r.series, p-value regression |
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Milestone: | → 7.0.0 |
Version: | unspecified → svn-releasebranch70 |
comment:2 follow-up: 3 Changed 6 years ago by
Cc: | pvanbosgeo added |
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You can calculate the p-value using the scipy library (from http://stackoverflow.com/questions/17559897/python-p-value-from-t-statistic). For example, if tt is the t value
import scipy.stats as stats import numpy as np tt = 2.4 n = 10 pval = stats.t.sf(np.abs(tt), n-1)*2 (two-sided p-value)
Perhaps this can be used either to create a script or in r.series?
comment:3 Changed 6 years ago by
Replying to pvanbosgeo:
You can calculate the p-value using the [python] scipy library
Considering that you want to calculate a p value for each single pixel, the chances that you get randomly some very small p values increase with the number of pixels. You would need to correct for that, with Bonferroni or some method that escapes the iron claw of Bonferroni. In any case, all your p values will most probably become not significant after any method of correction for multiple testing.
Therefore it is more appropriate to make prior assumptions about slope, intercept, and effect size, then judge the results according to these prior assumptions.
comment:4 Changed 4 years ago by
Milestone: | 7.0.0 → 7.0.5 |
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comment:5 Changed 4 years ago by
Milestone: | 7.0.5 → 7.3.0 |
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comment:7 Changed 2 years ago by
You can calculate regression p-value using R and the raster package. Here is a StackOverflow? post about it:
comment:9 Changed 21 months ago by
Milestone: | 7.4.1 → 7.4.2 |
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comment:10 Changed 17 months ago by
Milestone: | 7.4.2 → 7.6.0 |
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All enhancement tickets should be assigned to 7.6 milestone.
comment:11 Changed 13 months ago by
Milestone: | 7.6.0 → 7.6.1 |
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Ticket retargeted after milestone closed
comment:12 Changed 11 months ago by
Milestone: | 7.6.1 → 7.6.2 |
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Ticket retargeted after milestone closed
See especially