6P.10—Planning whole investigations

A complete plan states the hypothesis, variables, range, controls, method, repeats, risk assessment and analysis before data collection. The method must be feasible and ethically acceptable.

To test light intensity on photosynthesis, define a distance or light proxy, control temperature and CO₂, measure a rate, repeat each level and predict how a limiting factor might create a plateau.

Planning links the biological mechanism to the measurement, so the final conclusion can answer the original question rather than merely describe a graph.

A long method is not automatically valid: if the independent variable is confounded or the endpoint is vague, the plan cannot support causal inference.