VEP-UCD-001.txt 1.7 KB
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Vocabulary: http://www.ivoa.net/rdf/UCDlist/
Author: V.Delouille@oma.be
Date: 2021-05-04
Nb of terms discussed together : 3

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New Term: stat.skew
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Action: Addition
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Description: Statistical skewness, third moment of normalised data distribution function  
Prefix: P
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Rationale:
This term was proposed actually by Veronique Delouille after FITSKeyword evaluation for solar datasets.
Would complete the stat properties within the UCD tree.
Would be useful for other data as well.
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Used-in: SDO/AIA FITS keywords 
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Discussion:
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The statistical moments (except for the mean value) don't have the same units as the observed quantity, and thus those are another quantity extracted from the data. We propose to set the prefix to P.
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New Term: stat.kurtosis
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Action: Addition
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Prefix: P
Description: Statistical kurtosis, fourth moment of normalised data distribution function 
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Rationale:
This term was proposed actually by Veronique Delouille after FITS Keyword evaluation for solar datasets.
Would complete the stat properties within the UCD tree.
Would be useful for other data as well.
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Used-in: SDO/AIA FITS keywords
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Discussion:
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Skewness is related to the asymetry of the distribution, and the kurtosis help to identify outliers.
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New Term: stat.mad 
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Action: Addition
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Prefix: P 
Description: Statistical median absolute deviation from median
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Rationale:
This term was proposed actually by Veronique Delouille after FITS Keyword evaluation for solar datasets
this is a robust quantity to measure the spread of values in a data set when the statistic is not normal
Would complete the stat properties within the UCD tree.
Would be useful for other data as well.
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Used-in: 
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Discussion:
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Similar to stat.stdev, but using median operators instead of the mean.