P5.2—Planning experimental methods

A method must vary the independent variable deliberately, measure the response precisely, control key variables, include controls and collect enough results.

Choose volumes, concentrations, intervals and replicates that make the comparison fair; use serial dilution when appropriate.

Prepare a concentration series by proportional dilution, randomise treatment order if drift is possible and measure the same endpoint each time.

A control is a comparison condition, not simply a repeat with no label.