Statistics: Sampling Methods and Bias

Vocabulary flashcards covering types of sampling methods, randomization, and bias from introductory statistics lecture notes.

Census

A process or study that includes every member of a population.

Simple Random Sampling (SRS)

A sampling method in which each member of the population and each combination of individuals has an equal chance of being selected.

Probability Sample (Random Sample)

A sampling method that gives each member of the population a known chance of being selected.

Stratified Random Sample

A method that divides the population into homogeneous groups (strata) and selects a random sample from each group, often proportionally.

Multistage Sample

A sampling design that conducts sampling through many successive stages (e.g., country to state to county to school to classroom).

Systematic Sample

A sampling technique where a starting individual is chosen at random, followed by selecting every $k^{\text{th}}$ member of the population.

Cluster Sample

A sampling procedure that divides the population into heterogeneous individual units or groups, randomly selects one or more entire units, and conducts a census within those chosen units.

Randomization

A method used to protect against factors in the data you know about and those you do not know about, neutralizing the influence of all features of the population.

Bias

A systematic favoring of certain outcomes that consistently underestimates or overestimates the true value being measured.

under coverage

people are left out of the process of choosing the sample (under represents)

non response

when an individual chosen for the sample can’t be contacted or refuses to participate. (under represents)

voluntary response sampling

consists of people who choose themselves by responding to a general appeal. (in the process)

convenience sampling

we choose the individuals easiest to reach