unit 2 stats

descriptive statistics

stats that summarize and display data

population

represents all possible subjects of interest

sample

subset or portion of population chosen for study

cencus

collection of data for entire population

types of random sampling methods

simple random,

systematic random

stratified random

cluster random

simple random sample

individuals all have equal chance of being selected

systematic random sample

selects every kth subject on a list or sequence

stratified random sample

portions population into subsets called stratum and selects random sample from each stratum

cluster random sample

randomly selects a certain number of clusters and selects all participants in each cluster

non random sampling methods

convenience sample

quota sample

snowball sample

confounding variable

a third variable in a study that is associated with both the independent variable and the dependent variable

coverage errors

when the sampling frame excludes some segments of the target population

non response errors

when individuals who are sampled do not respond to the study or questions

measurement error

when the respondents answer inaccurately because of question wording or external influences

random experiment/trial

study in which participants are randomly assigned to a specific treatment

experimental group

group that receive treatment

control group

group that does not receive treatment

randomized control trial/experiment

trial where one group acts as an experiment group and the other is a treatment group

blinding

when participant and or researcher is not aware who is in the treatment and control or placebo group

single blind

when participants do not know if they are in treatment or control group

double blind

when participants and researchers do not know who is in which research group

observational studies

studies where no variable is manipulated only observed

types of observational studies

retrospective

prospective

case-control

retrospective study

data is from the past

prospective study

researchers follow participants into the future and record relevant variables

case-control study

comparisan studies between individuals whose have a condition (case) and those who do not (control)