0.4 experimentation

Non-experiments

Non-experimental research does NOT prove cause and effect.

Experiments

Experiments prove cause and effect

Dependent

• variable that is measured

  • reaction time

• Independent Variable:

variable that is changed

• Energy drinks vs no energy drinks

Operational Definitions

Reaction time, measured in milliseconds, for each participant is defined as the average score of 5 attempts on the Human Benchmark Reaction Test

Random Assignment

• Assign participants to experimental and control groups by chance.

• Without random assignment you cannot prove cause and effect!

Random Assignment controls for Confounding Variables

An outside factor that affects the results of an experiment

single blind study

only researcher knows treatment groups

double blind study

neither researcher nor participants know who receives the placebo or the real treatment

Experimenter Bias

placebo effect

a real phenomenon where a person experiences a positive (or negative, called nocebo) health improvement from a sham treatment