AP Stats Vocab Unit 10-11

Random

An outcome is random when you know what values can happen, but you do not know which specific value will happen

Simulation

A model of a real-world event using random numbers to mimic the outcomes and relative frequencies of the actual situation.

Component

The most basic random event in a simulation.

Trial

A sequence of several components that represent events you are pretending will happen.

Response Variable

The numerical result or outcome recorded for each trial.

Population

The entire group of individuals or instances you want to learn about.

Sample

A smaller, representative subset of the population examined to gather data.

Census

A sample that includes every single member of the population

Population Parameter

A numerical value or attribute that describes a characteristic of the entire population.

Sample Statistic

A value calculated from sample data used to estimate a population parameter.

Simple Random Sample (SRS)

A sample where every group of size \(n\) has an equal chance of being chosen.

Stratified Random Sample

The population is divided into homogeneous groups (strata), and an SRS is taken from each stratum.

Cluster Sample

The population is split into heterogeneous groups and all individuals in randomly selected groups are sampled.

Bias

Any systematic failure of a sampling method that favors a certain outcome or misrepresents the population.

Voluntary Response Bias

Bias that occurs when individuals can choose on their own whether to participate in a survey (often attracting strong opinions).

Convenience Sample

Sampling individuals who are easy to reach; this usually fails to represent the whole population.

Undercoverage

When a part of the population is given less representation or left out entirely in the sampling frame.

Nonresponse Bias

When a large fraction of randomly sampled people fail or refuse to respond.

Response Bias

Anything in the survey design or question wording that influences individual responses (e.g., leading questions).