Thread: What stats test for my A2 biology coursework?

Hi,
For my biology coursework i am investigating whether there is a relationship between position on the rocky shore for 4 different species of periwinkle and their tollerance to desiccation. I have collected all my data and have to include a statistical test.

My results are numbers of each of the species in 30 half metre quadrats starting at the sea level and moving up the shore. Each species has a different range in which they are found. The data with which i am looking for a correlation is a drop in mass of a number of the periwinkles over a 5 day period in which they were placed in a desiccator. There are 6 measurements for each species including the initial day 0 measurement. Please can someone help me out here. I study maths but only core and mechanics and i'm really out of my depth here. Thanks in advance.
The highest marks available for this section are awarded based on these criterea:

a) Data are processed using appropriate methods that reveal trends and patterns. The chosen statistical tests are appropriate
to the data to be analysed and the hypothesis to be tested. Calculations of statistical tests are clearly set out and
interpreted, using a null hypothesis and a 5% confidence level where appropriate. Trends and patterns are identified.
b) Results are interpreted using biological principles and concepts of Advanced GCE standard. Relevant biological principles
are applied correctly throughout.
c) Conclusions are supported by results. The limitations of results and the conclusions based upon them, are recognised and
evaluated. Any limitations of the procedure are commented upon, and sensible modifications are suggested.
To reach this level the whole analysis should be accurate and objective. Students must have selected their information carefully and applied it accurately. They should avoid sweeping generalisations and demonstrate an awareness that the conclusions they make are likely to lead to other questions or are part of a wider pattern of interactions.
A consideration of limitations must also include an analysis of the underlying principles and assumptions of the chosen methodology. Suggestions for modifications must be linked to such an analysis. Collecting more data or repeating again are not
suggestions that can be given credit at this level.

As you have more than 2 populations you should consider an ANOVA analysis.

Also in biology cluster analysis is very popular.

Cluster analysis - Wikipedia, the free encyclopedia

Thanks Pickslides after looking into ANOVA as best as i can it does seem like this would be an appropriate test. I'm just not sure about which version to use. It seems like there are fixed, random and mixed effects models and in some cases further subsets within these. Can you give me any guidance as to which type of ANOVA would be best?

Thanks

Paul