Research Methods Essentials

Sampling techniques determine who takes part in your study. Random sampling gives everyone an equal chance of being selected, whilst opportunity sampling simply uses whoever's available. Volunteer sampling relies on people putting themselves forward, and systematic sampling follows a predetermined pattern to choose participants.

Validity is crucial - it's whether your results are actually true and can be applied to real-life situations outside the research setting. External validity specifically asks whether your findings work in the real world, not just in your study.

Every experiment needs a clear aim (general statement of what you're investigating) and a hypothesis (specific, testable prediction about the relationship between variables). You'll manipulate the independent variable (IV) and measure the dependent variable (DV).

Extraneous variables are those annoying outside factors that can mess up your results. When they actually do affect the DV, they become confounding variables - the enemy of good research!

Quick Tip: Remember IV = what you change, DV = what you measure. Think "I manipulate the IV to see what happens to the DV."

Control techniques help you manage these problems. Random allocation puts participants into groups fairly, counterbalancing varies the order of conditions, and standardisation keeps procedures consistent across all participants.