Population vs Sample
A complete collection of individuals or units we want to study.
What is a population?
A sampling method where individuals choose to participate, often leading to bias.
What is voluntary response sampling?
A sampling method that divides the population into similar groups and randomly selects entire groups.
What is cluster sampling?
A study where researchers only observe subjects without imposing treatments.
What is an observational study?
A technique where subjects do not know which treatment they are receiving.
What is a single-blind experiment?
A subset of the population used to make inferences about the whole.
What is a sample?
A sampling method that selects individuals who are easiest to reach.
What is convenience sampling?
A sampling method that divides the population into groups based on a characteristic, then randomly selects individuals from each group.
What is stratified sampling?
A study where researchers apply a treatment and observe its effects.
What is an experiment?
A technique where neither subjects nor researchers know who received which treatment.
What is a double-blind experiment?
A method of collecting data from every individual in the population.
What is a census?
The tendency of a sample statistic to overestimate or underestimate a population parameter.
What is bias?
A method that randomly selects groups first, then randomly selects individuals within those groups.
What is multistage sampling?
A variable that influences both the explanatory and response variables, making it hard to establish causation.
What is a confounding variable?
A treatment with no active ingredient, used to measure psychological effects.
What is a placebo?
The numerical summary that describes a population.
What is a parameter?
A method where every individual has an equal chance of being chosen for the sample.
What is simple random sampling (SRS)?
A systematic way of selecting every k-th individual in a population after a random starting point.
What is systematic sampling?
The individuals or objects on which an experiment is performed.
What are experimental units?
The phenomenon where subjects experience changes just because they believe they received a treatment.
What is the placebo effect?
The numerical summary that describes a sample.
What is a statistic?
A type of bias that occurs when certain groups of the population are underrepresented in the sample.
What is undercoverage bias?
The difference between cluster sampling and stratified sampling.
What is 'cluster sampling selects entire groups, while stratified sampling selects individuals from each group'?
The explanatory variables that are manipulated in an experiment.
What are factors?
An experiment where subjects are grouped by a characteristic before random assignment.
What is a block design?