Stats

population

the entire group of individuals that we want to learn about

Sample

subset of the population that we use to collect information from

Sampling frame

list of the population members

inferential statistics

use the information collected from sample to make an inference about the entire population

statistic

a number that describes a sample

Descriptive statistics

sample information that statistics are based on

parameter

a number that describes a population, fixed values and typically unknown

voluntary response

voluntarily responding, method of obtaining a sample

bias

the survey either over- or under-estimates the actual population value

convenience sampling

respondents are chosen because they are the easiest to reach

random sample

free from sampling bias

simple random sample

a sample selected in a way that gives every individual in the population an equal chance of selection.

systematic sampling

a sample in which every kth object is selected from an ordered list

stratified sampling

sampling from a population which can be divided into subpopulations with shared characteristics called strata. each subgroup is randomly sampled

cluster sampling

random selection of groups of individuals of clusters. all individuals in each cluster are included in the sample

clusters

sample groups of individuals that are in close proximity to each other