Presenting Experimental Data
- There are many different types of experiments that can be conducted in biology
- The data collected from biological experiments can vary greatly across the subject
- For example, the large amounts of numerical data produced from ecological studies is very different to the drawings produced from microscope slides of live specimens
- The nature of an experiment dictates how the data should be presented
- It is important that scientists can make the correct judgment when deciding how to present data from an experiment
Collecting data
- Qualitative experiments involve collecting and recording observations
- Quantitative experiments involve collecting and recording numerical data
- Recording experimental data in a table is important for any type of experiment
- The table used will vary considerably depending on the specific requirements
- When constructing such a table:
- Draw lines with a ruler to separate cells
- Use appropriate headings
- Use the correct units and symbols (in the headings, not the cells)
- The independent variable should be in the first column
- Any dependent variable readings should be in the subsequent columns
Examples of a table that has been correctly constructed for an experiment
Processing data
- Depending on the type of experiment, data is processed using different methods (before being analysed)
- Some data does not require any processing, like drawings from life
- Qualitative results can't be processed mathematically (there isn't any numerical data) but the observations can be analysed
- The observations may be compared to a standard or other experimental work
- Quantitative results must be processed using mathematical skills prior to analysis
- Simple calculations work out means and rates
- Further calculations are done to obtain information surrounding means (standard deviation and standard error)
- Statistical tests are performed to better understand the results (chi-squared and t-test etc.)
- In addition to these mathematical calculations, the data can be presented in graphical form
- Graphs, bar charts, and histograms can be used to display quantitative data
- The type of graphical format used depends on the data
- For qualitative and discrete data, bar charts or pie charts are most suitable
- For continuous data, line graphs or scatter graphs are most suitable
- Any graph drawn should have:
- The appropriate scale with equal intervals
- Labelled axes with the correct units
- Straight lines drawn with a ruler
The line graph has been used to display continuous data over time while the bar chart has been used to display grouped data