The definition of "sufficient relevant data" depends on the context. The planned investigation should: Anticipate the collection of sufficient data so that the aim or research question can be suitably addressed and an evaluation of the reliability of the data can be made. If error analysis involving the calculation of standard deviation is to be carried out, then a sample size of at least five is needed. The data range and amount of data in that range are also important from: IB Internal Assessment Online Workshop, 2009
Range of data required for PreAP is 3 different points. Example: If you were changing temperature to see the effect on plant growth, then you would need to run the lab at three different temperatures. The more temperatures you chose the better. IB and AP Biology require a minimum of 5. It should also be noted the amount of data collected effects the quality of your analysis. The more data you have, the better your analysis will be.
Sufficient data collected in each range refers to the number of trials run. PreAP is required to run at least 3 trials per independent variable change. IB and AP Biology are required to run a minimum of 5. Using the above example this would mean for a PreAP Biology lab the student would choose the three temperatures to run the experiment (range of data) AND for EACH temperature they would run the experiment three times. Again, the more data collected, the better your analysis will be (and sometimes easier).