Recent content by zwergje

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    Normality of the data in linear regression

    Hi, the data set represents different sweet water reservoirs in Spain. I believe it is likely that Zebra mussel density is the only explanatory variable, and all others are responsive water quality indicators since the invasive Zebra mussel is known for its negative effects on water quality. The...
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    Normality of the data in linear regression

    Hi, thanks for your reply. Closer consideration made us change the idea of what is the predictor/ independent variable and what are the response variables. Since zebra mussels are an invasive species with a negative effect on aquatic ecosystems and water quality and the other two (zooplankton)...
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    Normality of the data in linear regression

    We have a data structure with 11 columns: 3 species and 8 chemical-physical indicators of water quality. However, two of the species are zooplankton well known for their use as biological indicators of water quality. That's why it seemed likely that we have only one variable (zebra mussel...
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    How to interpret my CCA triplot?

    How to interpret my CCA triplot? I have a CCA triplot of taxa/ samples over 8 environmental gradients and am trying to make sense of the result. First, different theory sources all state that clustering of samples around the far end of an arrow representing an environmental gradient suggests...
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    The length of explanatory vectors in CCA and their relation to impact on (explained) variance

    I performed CCA on a taxa-sample matrix using 8 explanatory variables. They say that the length of the vectors that represent the explanatory variables in your triplot visualization is proportional to their impact on the taxonomic variance. However, since various of my explanatory variables have...
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    Canonical Correspondence Analysis: how to interpret results

    Continuing this topic, I would like to ask the following: how can the strength of the explanatory variables ( = lengths of the arrows in the CCA triplot) be assessed? Do the result supply some numbers that relate to the strength of each explanatory variable?
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    Canonical Correspondence Analysis: how to interpret results

    Hi, thank you for your response with helpful link. Since time is limited and work overwhelming, I posted on several locations. I was lucky enough to receive an answer from an absolute authority on the matter, in one of the authors of the source article. It confirms what you say. In order to...
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    Canonical Correspondence Analysis: how to interpret results

    Hi, I am using Canonical Correspondence Analysis (CCA) to analyze phytolith abundances (similar to pollen) over environmental gradients. As I am new to CCA, I read some background info. The following section from explains how to look at the visualization of results (Buttigieg & Ramette, 2014)...