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Presence/ Absence similarities
There are numerous similarity measures defined for simple species lists, i.e. when the data consi...
Quantitative measures on P/A data; Unravelling resemblances; Scatter plots
It is instructive to draw the other links between quantitative coefficients and the presence/abse...
Quantitative similarity measures
In addition to Bray-Curtis $S_{17}$, and its zero-adjusted modification, PRIMER 7 also calculates...
‘Modified Gower’
Anderson MJ, Ellingsen KE, McArdle BH 2006, Ecol Lett 9: 683-693 used Czekanowski’s mean characte...
Accessing other resemblance measures
PRIMER 7 allows the user choice of 44 other resemblances, firstly divided into two (mutually excl...
Index of Association
The remaining of the three choices in the initial list, Measure•Index of Association, is essentia...
Euclidean distances
Euclidean distance, an appropriate measure for environmental (and other) data types, is defined a...
(Tikus Island coral cover)
Data on coral communities at a site in Tikus Island, Thousand Islands, Indonesia, over the years ...
Zero-adjusted Bray-Curtis
A simple modification to the Bray-Curtis coefficient adjusts its behaviour as samples become vani...
Bray-Curtis similarity
The most commonly-used similarity coefficient for biological community analysis, because it obeys...
Standard resemblance choices
A detailed discussion of the competing properties of different resemblance matrices is outside th...
Resemblance matrices
Fundamental to the operation of PRIMER and (explicitly or implicitly) any fully multivariate anal...
Surface plots
The smoothing effect can best be seen by Plots>Surface Plot of both Data1 and Data2 sheets – a fu...
(Biomarkers for N Sea flounder)
The directory C:\Examples v7\N Sea biomarkers holds a data sheet N Sea flounder biomarkers(.pri) ...
Variability weighting
Pre-treatment>Variability Weighting is a new option in PRIMER 7, which bears similarities to the ...
Other variable weighting
There are other cases in which variables (species) might need prior weighting, e.g. when a specie...
(Fal estuary copepods)
Sediment copepod assemblages (and other fauna) from five creeks of the Fal estuary, SW England, w...
Dispersion weighting of species
When variables are on different measurement scales, there is little viable alternative to normali...
Normalising variables
It is typical of a suite of physico-chemical variables (or biomarkers, water-quality indices etc....
Transforming (individual)
Both the Draftsman and Histogram Plots show that several of the Ekofisk abiotic variables are hig...