AP Statistics - Unit 4 Vocab

all vocab terms for unit 4

Sample Survey (4.1)

An inquiry that asks questions of individuals drawn from a population (such as a poll)

Census (4.1)

A sample that consists of the entire population

Population (4.1)

The entire group about whom a statistician hopes to learn

Sample (4.1)

A portion of a population examined to learn about that population

Population Parameter (4.1)

A numerical attribute for an entire population (rarely know this)

Sample Statistic (4.1)

A numerical attribute calculated for sampled data and used to infer the associated population parameter

Sample Size (4.1)

The number of individuals , n , in a sample

Randomization (4.1)

Each individual is given a fair, random chance of selection

Representative (4.1)

The sample statistic(s) computed from a sample accurately reflect(s) the corresponding population parameter (s) ...you took a "good sample "

Simple Random Sampling (SRS) (4.1)

Each combination of n individuals in a population has an equal chance of selection...often done by assigning a number to each individual and generating n random numbers

Stratified Random Sampling (4.1)

Sampling method where the population is divided into several homogeneous subsets (called strata) and THEN random samples are proportionally drawn from each stratum

Cluster Sampling (4.1)

Sampling method where entire groups or "clusters" of subjects are selected at random; the clusters must be heterogeneous and individually representative of the population

Systematic Sampling (4.1)

Sampling method in which subjects are listed and one subject is selected, followed by each of the next nth subjects

Sampling Variability (4.1)

The natural tendency of randomly drawn samples to differ from one another

Sampling Bias (4.2)

Systematic failure of a sampling method to properly represent its population

Voluntary Response Bias (4.2)

Individuals must volunteer or take some prior action t o be included in a sample

Convenience Sampling Bias (4.2)

Subjects chosen for a sample are simply those conveniently available due to some factor

Undercoverage Bias (4.2)

Some portion of the population is not sampled at all or has a reduced chance of being included in the sample

Nonresponse Bias (4.2)

A substantial fraction of those properly sampled fail to respond

Response Bias (4.2)

Anything in a survey design that influences the responses, such as wording survey questions in a way that suggests a favored response or perceived pressure in the survey

Observational Study (4.3)

Study in which the researchers do not assign treatments , they simply observe them

Retrospective Study (4.3)

Observational study in which subjects are selected and then their previous conditions or behaviors are observed

Prospective Study (4.3)

Observational study in which subjects are selected and then followed to observe future outcomes

Experiment (4.3)

An experimenter controls factor levels to create treatments, randomly assigns subjects to those treatments, replicates the experiment with all of th ose subjects, and then compares the responses of the subjects

Completely Randomized Design (4.3)

Every subject and combination of subjects has an equal chance of receiving each treatment

Factor (4.3)

An explanatory variable whose levels are controlled by the experimenter

Response Variable (4.3)

The variable whose resulting values are compared across different treatments

Level (4.3)

The specific value that the experimenter chooses for a factor

Treatment (4.3)

The controlled circumstances applied to experimental groups, made of different levels of a single factor or combinations of two or more factor levels.

Control Group (4.3)

A baseline treatment level that provides a basis for comparison ; often either a well - understood level or a null treatment

Subject/Experimental Unit (4.3)

Individuals or objects on whom an experiment is performed

Randomization (4.3)

An experiment must assign subjects to treatment groups at random

Replication (4.3)

Each treatment must be repeated for multiple subjects

Statistically Significant (4.3)

When an observed difference is too large to believe that it was likely to have occurred naturally (we will be far more specific on how to formally make that determination next semester)

Single-Blind (4.3)

When either the subjects themselves or the administrator s/ evaluators in an experiment are unaware of which subjects were assigned to each treatment group

Double-Blind (4.3)

When both the subjects themselves and the administrators/ evaluators in an experiment are unaware of which subjects were assigned to each treatment group

Placebo (4.3)

A treatment known to have no effect, administered to the control group so that all groups experience the same condition (such as a sugar pill)

Placebo Effect (4.3)

A perceived reaction to a n ineffective treatment ...must compare to a place bo to be sure that the observed effect of a treatment is not simply due to the placebo effect

Blocking (4.4)

Grouping subjects together by uncontrollable attributes, thus allowing an experimenter to isolate the variability attributable to differences in the blocks and see the differences caused by the treatments more clearly

Randomized Block Design (4.4)

Experimental design in which randomization occurs only within blocks; treatment groups are not mixed for different blocks

Confounding Variable (4.4)

When the levels of one factor are associated with the levels of another factor and thus their effects cannot be separated

Matched Pairs Design (4.5)

Experimental design where the same individual for multiple treatment trials or individuals with similarities not under study are paired together when undergoing the experiment, hopefully reducing the variation in the data from other factors

Multi-Factor Design (4.5)

Experimental design in which you study the effects of multiple uncon trollable factors at the same time

All experiments need...

CCRR (Control, Comparison, Replication, and Randomization)

Acronym for Completely Randomized Design

Fat Rats Like To Sit Along Big Dirty Roads (Factor, Response Variable, Levels, Treatments, Subjects, Assignment, Blinding, Diagram, Results)

Acronym for completely Randomized Block Design

Fat Rats Like To Sit Boldly Along Big Dirty Roads (Factor, Response Variable, Levels, Treatments, Subjects, Blocking, Assignment, Blinding, Diagram, Results)