Fieldwork: Spearman's Rank Correlation Coefficient

A simple statistical test examining the relationship between 2 sets of data.

95% significance: 0.377       99% significance: 0.534

For % of vegetation cover: +0.41 so there is a 95% certainty that it and distance from the sea are related.

For number of plant species: +0.47 so there is a 95% certainty but is more than vegetation cover

There is a moderate positive correlation.

Given that we had had 20 sites we can say with certainty that there is a 95% correlation between the variables. We can't be 99% sure.

Advantages:

• Tells whether direction of relationship is positive or negative
• Tells exactly the strength of the relationship unlike the scattergraph which only gives a general indication

Disadvantages:

• Correlation does not equal causation
• Simplistic technique
• Need at least 10 sets of data