Note the Variance Inflation Factor (VIF) values. A VIF above 10 indicates appreciable
multicollinearity. In the above table it is clear that the Manure variable is highly
correlated with a combination of other variables. Manure should probably be removed
from the analysis. But first we can see if Manure is highly correlated with any other
single environmental variable.
Click on the Scatter Plot tab. Select Manure in Plot (x Axis) and each of the other
environmental variables in turn in the y axis menu box. If you activate the box you
can use the up and down arrows to swiftly move through the variables. Make sure you
have selected Env. in the Plot radio button or you will only be offered the species!
The scatter plot of Manure against SF indicates a Pearson correlation between these
variables of 0.72. Evidently the standard farming variable and Manure are related.
This increases our suspicion that Manure or possibly SF should be removed from the
We will not remove any variables from the present analysis but for future reference
this is done using the Deselect Row in the Working Environmental data tab.
It is often useful to identify the top 1, 2 or 3 environmental variables for inclusion in
the final analysis. This can be done using the
drop down menu.
The next stage is to
interpret the results
Copyright 2004 PISCES Conservation Ltd