Statistics ch1-ch5 Flashcards
population
the larger group from which the sample was chosen from.
seven critical components
1.source
2.researchers
3.indivduals or objects studied
4. measurements
5.setting
6. extraneous differences
7. magnitude
categorical variable
those that divide subjects into groups, but do not allow any sort of mathematical operations to be performed on the data.
measurement variables
those for which the responses are meaningful numeric values.
nominal variables
categorical variables for which the categories do not have a natural ordering
ordinal variables
categorical variables for which the categories have a natural ordering.
interval variables
measurement variables for which differences are consistent, but ratios are not.
ratio variables
measurement variables for which ratios are consistent.
Discrete measurement variables
those with a countable number of possible responses.
continuous measurement variables
those that may assume any number in some interval. Every fraction is a possible value.
Bias
a systematic prejudice in one direction
anchoring
information provided in one question may suggest a response to a later question.
variability
discrepancies between repeated measurements.
natural variability
variability that cannot be explained or predicted.
valid measurement
measures what it claims to measure
reliable measurement
gives approximately the same result when repeated on the same subject.
confidential
respondents identities are known but protected.
anonymous
respondents’ identities are unknown.
open questions
essay, short answer
closed question
multiple choice
unit
single individual or object
population
collection of all units of potential interest.
sample
collection of units upon which we actually take measurements
frame
a list of units from which the sample is chosen
census
a survey in which the entire population is measured.
simple random sample
a sample collected in such a way that every conceivable group of units of the correct size has an equal chance of being the one selected.
margin of error
a measure of sampling error
Stratified random sample
Divide the population into groups and then collect a simple random sample form each group.
Cluster sample
Divide the population into groups. Take a simple random sample of clusters and measure all units within the selected clusters.
Systematic sampling
Select units from the frame according to some pattern.
Multi-stage sampling
A sampling plan that combines two or more sampling procedures.
Response variable RESP
The primary measurements of interest. Usually a study considers only one RESP.
Explanatory variables
Information about each subject that may explain why the subjects differ with respect to the RESP. studies often consider several EXPL.
Experimental study
A study in which EXPL is controlled by the research. An EXPL whose value is determined by the research is called a treatment.
Observational study
A study in which the value of the EXPL is determined by nature. The EXPL in an observational study is not controlled or manipulated by research.
Confounding variable
Is a variable that is related to both the EXPL and the RESP. A confounding variable is an extraneous difference in the group.
Interacting variable
A variable that interacts with the EXPL is a variable that changes the way the groups compare with respect to the RESP. Two variable are said to interact if the effect one variable has on the RESP depends on the value of the other variable.
Control group
A treatment group that receives essentially no treatment
Placebo
A fake drug that looks like a real drug but has no active ingredients
Placebo effect
The tendency of subjects to respond to any treatment even a fake one
Hawthorn effect
The tendency of subjects to react differently than they normally would because they are being observed.
Experimenter effects
The tendency of researchers to see what they want or expect to see.
