AP Stats Unit 3

simulation

The imitation of chance behavior, based on a model that accurately reflects the experiment under consideration.

stopping rule

A guideline indicating when to stop the simulation, e.g., 'continue selecting until...'.

population

The entire group of individuals we want information about.

census

A complete count of the population; gathering information about the entire population.

sample

a part of the population we actually examine in order to gather information

sampling design

The method used to choose the sample from the population.

bias

A systematic error in measuring the estimate that would repeatedly cause the data to be wrong.

voluntary response bias

When individuals select themselves to participate in the study.

nonresponse bias

individuals who are randomly chosen for the sample cant be contacted or refuse to cooperate

convenience sampling

asking people who are easy to ask; convenient but not random

under coverage bias

some groups are left out of the selection process

response bias

the behavior of the respondent or interviewers causes you to get incorrect answers

wording bias

when wording of the question influences the answers that are given

sampling frame

A list of every individual in the population.

simple random sample

A sampling method where every individual has an equal chance of being chosen.

stratified random sample

A method where the population is divided into strata and a simple random sample is used on each stratum.

systematic random sample

A sampling method that involves randomly selecting a number between one and n and surveying every nth person thereafter.

cluster random sample

A sampling method where a location is randomly picked and all individuals from that location are sampled.

multistage sample

a combination of different sampling techniques

matched pairs design

A special type of block design where experimental units are matched according to similar characteristics.

completely randomized design

experimental units are assigned completely at random to treatments

randomized block design

experimental units are blocked in homogeneous groups and then randomly assigned to treatments

observational study

A study where outcomes are observed without imposing any treatment.

experiment

A study where a randomly assigned treatment is actively imposed to observe the response.

experimental unit

the single individual to which the different treatments are randomly assigned

factor / explanatory variable

what we test or what we change

level

a specific value or type for the factor

response variable

what you measure or record at the end of the experiment

treatment

a specific experimental condition applied to the units

control group

A group used to compare the factor against; can involve a placebo.

placebo

A 'dummy' treatment that can have no physical effect, not required in every experiment.

blinding

A method used so that units or evaluators do not know which treatment units are receiving.

double blinding

neither the units nor the evaluators know which treatment a subject recieved

confounding variable

A third variable that potentially affects both the factor and the response variable.

replication

Repeating the experiment on many subjects to quantify the natural variation in the experiment.

systematic random sample

number all ___ and place ___ numbers in a hat. Mix and randomly select one number and survey the corresponding person. Survey every nth person on the list after that.

cluster random sample

number all clusters and put the numbers into a hat Mix and randomly select a number from the hat. Survey everyone in that cluster.

stratified random sample

sort everyone into strata then number ___ in all the stratum. place the numbers in a hat and draw __ numbers. survey the corresponding people in that specific stratum. repeat the process for all strata