Planning fair tests, sampling and risk assessment

By the end you’ll be able to

• plan a fair test by identifying the independent variable, dependent variable and control variables and by describing how variables are controlled
• design a practical method that gives valid and reliable data, including the use of repeats, suitable sample size, controls or comparison groups, and a clear sequence of steps
• distinguish between random error, systematic error and contamination in practical work and describe design choices that reduce these problems