Vocabulary
This is the entire group we want information about.
What is a population?
Choosing people who are easy to reach is this type of sampling.
What is convenience sampling?
A study where the researcher only observes people.
What is an observational study?
The group that receives the treatment.
What is the treatment group?
This happens when two variables get mixed up and you can’t tell which caused the effect.
What is confounding?
This is a smaller group selected from the population.
What is a sample?
Choosing every 5th student from a list is this type of sampling.
What is systematic sampling?
A study where researchers apply a treatment to subjects.
What is an experiment?
A fake treatment that looks real.
What is a placebo?
People lie or misremember when answering a survey.
What is response bias?
A number calculated from a sample is called this.
What is a statistic?
Dividing the population into groups and selecting some from each group.
What is stratified sampling?
A study comparing smokers vs non‑smokers for lung cancer risk.
What is a case‑control study?
When a person feels better because they believe they got treatment.
What is the placebo effect?
A question that pushes someone to choose a certain answer.
What is a loaded question?
Data made of numbers where math calculations make sense.
What is quantitative data?
Selecting whole clusters like classrooms or city blocks.
What is cluster sampling?
This type of study can NEVER prove causation.
What is an observational study (or case‑control study)?
In this type of study, neither the participants nor the evaluators know the group assignments.
What is a double‑blind study?
A weight‑loss pill study also tells participants to diet and exercise.
What is confounding? (diet and exercise)
A group that does not receive treatment is called this.
What is the control group?
This kind of bias happens when your sample does not represent the population.
What is sampling bias?
A study that uses pre‑existing differences and looks backward for causes.
What is a case‑control study?
Plants don’t need this in experiments because they have no expectations.
What is a placebo? (or: Why is a placebo unnecessary for plants?)
Only people with strong opinions answer this type of survey.
What is voluntary‑response bias?