Pearson Science Double Award Practical 3: Tables, Graphs and Calculations

Data handling should expose the tested relationship without hiding repeats, units, scatter or anomalous results. In 4SD0, the same principles apply to biological samples, chemical reactions and physical measurements even though the scientific interpretation differs.

Build a raw-data table

Put the independent variable in the first column and the dependent measurements to the right. Write quantity names and units in headings, such as “temperature / $\pu{\degreeCelsius}$” or “oxygen volume / $\pu{cm3}$.” Do not repeat units in every cell.

Keep raw repeats visible before calculating a mean. Use consistent decimal places within a column when readings come from one instrument. Record observations such as colour, precipitate or organism behaviour in clearly labelled qualitative columns rather than forcing them into invented numbers.

Arrange independent-variable values in a logical order. Include uncertainty or resolution only when it is known and useful. A calculated column should state the calculation, such as mean rate, percentage change or reciprocal time.

Process repeats and anomalies

A mean represents repeated measurements only when combining them is justified. Inspect spread first. An anomalous result differs substantially from the pattern or other repeats, but it should not be deleted merely because it weakens a conclusion.

Repeat the condition when possible. Retain the original raw value, mark the suspected anomaly and state whether it is excluded from a mean with a reason. Median may be more robust for skewed biological data, but use it only when the question or data structure supports that choice.