AP Statistics: Sampling Methods, Experimental Design, and Sources of Bias

Vocabulary flashcards covering core concepts of observational studies, sampling methods, experimental design, and survey biases based on the lecture notes.

Population

The entire group of people or objects you want to study.

Sample

A smaller group selected from the population to be studied.

Sampling Method

The way individuals or objects are selected for a sample.

Simple Random Sample (SRS)

A sample in which individuals are randomly selected from the entire population.

Stratified Random Sampling

A sampling method that divides the population into groups and randomly selects individuals from every group.

Cluster Random Sampling

A sampling method that divides the population into groups, randomly selects some groups, and studies everyone in those selected groups.

Systematic Sampling

A sampling method that selects individuals using a regular pattern or fixed interval, such as every fifth person.

Undercoverage Bias

Bias that occurs when some groups in the population are left out or inadequately represented.

Voluntary Response Bias

Bias that occurs when people choose for themselves whether to participate in a survey.

Non-Response Bias

Bias that occurs when selected individuals do not respond and their opinions may differ from those who respond.

Response Bias

Bias that occurs when answers are inaccurate because of how questions are worded or how people respond.

Random Selection

Choosing individuals or groups by chance rather than personal preference.

Random Digits

Randomly generated numbers used to select individuals or objects for a sample.

Random Digits Selection Procedure ($00$–$19$)

Reading two digits at a time and ignoring numbers outside $00$–$19$ as well as repeated selections.

Random Assignment

Placing participants into experimental treatment groups by chance rather than personal preference.

Experiment

A study in which researchers deliberately apply treatments to investigate their effects.

Experimental Units

The individuals or objects that receive the treatments in an experiment.

Factor

An explanatory variable that researchers deliberately change in an experiment.

Levels of a Factor

The different values or settings of a factor.

Treatments

The specific conditions applied to experimental units in an experiment.

Response Variable

The outcome that researchers measure in an experiment.

Explanatory Variable

A variable used to explain or predict changes in the response variable.

Replication

Applying each treatment to multiple experimental units.

Control Group / Control Treatment

A baseline condition used for comparison with other treatments.

Lamb Experiment: Variables

An experiment where the explanatory variables are roasting time and roasting temperature, and the response variable is the quality of the finished lamb.

Lamb Experiment: Replication

Cooking two cuts of lamb for each time-temperature combination.

Bird Experiment: Experimental Units

The $40$ individual European starlings.

Bird Experiment: Factor and Levels

One factor (garlic oil concentration) tested at five levels: $0\%$, $2\%$, $10\%$, $25\%$, and $50\%$.

Bird Experiment: Treatments and Control

Five treatments corresponding to each concentration level, with the $0\%$ garlic oil concentration serving as the control treatment and $8$ birds receiving each treatment.

Bird Experiment: Response Variable

The number of food granules consumed by each bird during the two-hour period.