Collating and analysing the results

All observations need to be recorded. It is vital that data is recorded accurately and also that all the data is retained. Never discard data on the basis that it does not fit into what your expected outcome is.

It is important that a detailed understanding of the experiment is obtained before it is performed and data collected matches what is required by the hypothesis and the statistical tests to be undertaken.

Data sheets

When collecting data the first stage is to identify what data is needed to test the hypothesis and then design an appropriate data sheet to aid in its collection.

Ideally data should be collected by one person, as this eliminates any bias that may occur from different recorders. However, this is not always possible and where different recorders are used, procedures for collecting and recording the data should be devised and explained. It is also a good idea to have a set of clear instructions displayed in a prominent place for easy reference, for example, on the data collection file.

The data sheet should include:

• space for all relevant information to be recorded

• an area to identify who recorded the information as this will help identify any bias if necessary

Design the data sheets according to the type of information that needs to be collected. Here are some examples of data sheets for recording information from a diet trial.

Summarising data

For ease of use, data can be summarised into tables but all raw data should be retained for future reference. Once the raw data has been obtained it can then be tabulated or graphed. This will allow any obvious trends to become apparent and will help the experimenter in the analysis of the results.

Results

The results obtained should be analysed statistically to test whether the hypothesis proposed is true or not. There are several statistical tests that can be employed, depending on the requirements. An overview of these tests can be found in Chapter 5 of the Aquaculture Textbook.

Here is an example of how information from a diet trial can be tabulated to make it more meaningful and easier to interpret.

Example

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