statistics terms

unit 8 math 3 terms for statistics

study type: survey

obtains data from a subset of population through survey or poll.

study type: observational

• data are observed and collected on each subject

• no manipulation of subject’s environment occurs

study types: experiment

• manipulate subject’s environment

• a “treatment" is imposed & there is a control group

sampling types: simple random sample

• each subject has equal opportunity of being selected.

• ex: random number generator

sampling types: convenience

• its easy, quick and inexpensive

• typically leads to bias

• ask ppl close by, as they leave a place, family

sampling types: systematic

• pick a starting point, then select every “n” object

• example: every 3rd person in the row.

sampling types: voluntary

• subjects volunteer to be part of the sample

sampling types: cluster

• where a population is divided into pre-existing groups and some groups are randomly selected and everyone inside the group is surveyed.

sampling types: stratified

• groups are chosen to represent the population, and a random sample from each group is taken.

sampling bias

some members of the intended population have lower chance of being selected than others.

sampling bias: under coverage

some members of the population are inadequately represented.

sampling bias: non-response bias

members of the sample are unwilling to participate in the survey.

sampling bias: response bias

give false or misleading answers

sampling bias: question wording

wording is confused or misleading

sampling bias: voluntary response

are self self selected volunteers