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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...
Draftsman, histogram & multi-plots
Temporarily deselect the Distance (as in Section 3), and run Plots>Draftsman Plot on the other 9 ...
Transforming abiotic variables
Transformations may be appropriate for environmental variables too, though usually for a differen...
Shade plots to aid choice of transform
A major new feature in PRIMER 7 is the large number of additional plotting routines, one of the c...
A2 References
Akaike (1973) Akaike H. 1973. ‘Information theory as an extension of the maximum l...
Transforming (overall)
Transformation is usually applied to all the entries in an assemblage matrix of counts, biomass, ...
Standardising species
Pre-treatment>Standardise can also be used to standardise the matrix on the variables axis, e.g. ...
Stats to worksheet
Several of the routines in PRIMER 7 also incorporate a check box for sending summary statistics u...
Selection in resemblance matrices
Looking ahead to Section 5, when the active window is a (triangular) resemblance matrix, selectio...