Stats defs

Population

all the people in a group

Sample

The part of the population selected for analysis

Parameter

a numerical characteristic of a population, often used to summarize or describe it

Statistic

A numerical characteristic of a sample

Variable

The question

Categorical

Questions asked and answered with words

Quantitative

Questions answered with numbers exceptions: zip codes, etc

Quantitative Discrete

countable, finite ex: # of students

Quantitative Continuous

Can measure, infinite ex: weight, distance

Simple Random SRS

Sample selected in such a way that every possible subject has the same chance of being chosen ex: number generator, coin flip

Systematic

A sample where every kth subject is selected

Stratified

A sample that is divided into groups with the same characteristics and then randomly sample some from each group

Cluster

A sample that is divided into mixed groups and then all members are sample from some of the randomly selected groups

Convenience

A sample that was selected in n easy way

Voluntary response

Sample compromise of respondents who decide whether or not they want to be included