Descriptive stat= describe data through numerical summaries and graphs
Variables=characteristics of indiv with the pop
Discrete=count, continuous=measure. Nominal=name, ordinal=rank or order, Interval=0 has no meaning same space between 3's, ratio=0 has meaning
Response= what is being studied, explanatory=how much variable affects response, confounding=not seperating factors that affect response, lurking=variable that was not considered in study. Studies only show association. Cross sectional=group of people in a short time, case-control=look to the past to find answers, cohort=group of people over a very long time.
Random sampling= using chance to select individuals, simple random=selecting names from a hat or random chart, Stratified= cheaper than random;obtained by separating the pop into different groups then obtaining a simple random sample from each stratum, systematic=selecting every nth individual from pop; p - p+k - p+2k -.....P+(N-1)k..N=pop size
Cluster=selecting all individuals within randomly selected collection.
Bias=sample are not representative of pop, sampling bias=undercoverage or favors one part of pop, non response=individ may not respond and have a different opinion, response= can result from answers not being worded right
Experiment=study conducted to determine the effect of 1 or more explanatory has on a response, treatment=combination of the values or factor, Experimental unit= person being studied; Matched pairs=before and after husband and wife