● Population: Includes all people or items with the characteristics one wishes to understand.
● Sample: A subset of the population.
● Census: An official count or survey of a population, typically recording various details of individuals.
● Voluntary Response Sample: Consists of people who choose themselves by responding to a general appeal.
● Explanatory Variable: The variable that affects the response variable
● Response Variable: The variable that is expected to change with the explanatory variable
● Confounded: Two variables whose effects on a response variable cannot be distinguished from each other.
● Convenience Sampling: When individuals who are easiest to reach are chosen.
● Simple Random Sample (SRS): Of size “n” consists of “n” individuals from the population chosen in such a way that every set of “n” individuals has an equal chance to be the sample actually selected.
● Stratified Random Sample: Take a population, then divide the population into groups of similar individuals (strata). Afterwards, choose a separate SRS in each stratum.
● Systematic Sample: Every “nth” person is chosen for the sample.
● Cluster Sample: A sample consisting of a whole group.
● Biased: Systematically favors certain outcomes.
● Undercoverage Bias: When some group of the population are out of the process of choosing the sample.
● Response Bias: Occurs when an individual responds in a false way.
● Non-Response Bias: Occurs when an individual chosen for the sample cannot be contacted or refuses to cooperate.
● Wording Bias: In a survey, when a question is worded in such a way that influences what a subject might respond.
● Observational Study: Observes individuals and measures variables of interest but does not attempt to influence the response.
● Experiment: Deliberately imposes some treatment on individuals in order to observe their response.
● Replication: Repeating the experiment many times, under the same conditions, but with different subjects.
● Control Group: A group of patients who receive a sham treatment called the placebo (e.g. sugar pill).
● Randomization: All the experimental units are allocated at random among all of the treatments
● Treatment: A specific experimental condition applied to the units.
● Double-Blind Procedure: Neither the subjects nor the people who are in contact with them know which treatment a subject received (only a third party knows).
● Block: A group of experimental units or subjects that are similar in ways that are expected to affect the response to the treatments.
● Match Pairs Design: Assigning subjects with similar characteristics and giving one group the treatment and the other the placebo. Another design is giving the same subject a treatment and determining before and after if it had an effect on the subject.
• “I will number [the n subjects] 000 (put as many zeros as digits in n - 1) to [n - 1]. I will read [the number of digits in n - 1] digits at a time, ignoring repeats and numbers above [n - 1] (only applies if n - 1 is not 9, 99, 999, etc.). The first [number of subjects you want] [subjects] will [receive treatment 1]. The next [number of subjects you want] [subjects] will [receive treatment 2] (repeat until you have all the subjects assigned to treatments).”