P5.4—Dealing with experimental data

Present the key values in a clear table or graph, put the independent variable on x and the dependent variable on y, and choose calculations that answer the question.

Use means, percentages, percentage change or rates only when the underlying units and comparison are clear.

A percentage increase should state the baseline used; a rate should state the interval over which it was calculated.

A graph can clarify data but cannot repair an unsuitable scale, missing units or selective omission.