STATS Unit 3 vocab

treatment

A specific condition applied to the individuals in an experiment

sampling variability

Different random samples of the same size from the same population produce different estimates

response bias

There is a consistent pattern of inaccurate responses to a survey question

bias

Underestimates or overestimates the value you want to know when the study is repeated many times

simple random sample

Sample chosen so that every group of n individuals has an equal chance of being selected

control group

A group used to provide a baseline for comparing the effects of other treatments

sample

A subset of individuals in which we collect data from in a statistical study

observational study

Observes individuals and measures variables of interest

nonresponse

An individual chosen for the sample can't be contacted or refuses to participate

cluster random sample

Sample formed by randomly selecting clusters and including each member of the selected group in the sample

convenience sample

Choosing individuals from the population who are easy to reach

placebo

A treatment that has no active ingredient, but is otherwise like other treatments

experiment

Deliberately imposes some treatment on individuals to measure their responses

census

Collecting data from every individual in the population

stratified random sample

Sample chosen by selecting an SRS from each stratum

single blind experiment 

Either the subjects don't know which treatment they are receiving or the people who interact with them and measure the response variable don't know which subjects are receiving each treatment

population

The entire group of individuals we want information about in a statistical study

voluntary response sample

People choose to be in the sample by answering a general invitation

confounding

Two variables are associated in such a way that their effects on a response variable cannot be distinguished from each other

undercoverage

Some members of the population are less likely to be chosen or cannot be chosen for the sample

double blind experiment

Neither the subjects nor those who interact with them and measure the response variable know which treatment a subject received

placebo effect

Some subjects in an experiment will respond favorably to any treatment, even an inactive treatment