variation that denotes an anomaly or inaccuracy in observations which are the factors not under statistical control. consistent
systematic variation
variation that is random/haphazard. not consistent
unsystematic variation
when each participant has a 50% chance of assignment to either group
simple randomization / random assignment
when a random group is chosen from a population to be studied
random sampling
What is considered the ideal experiment?
having random assignment and random sampling
experimental design that includes some control over variables but doesn’t randomly assign participants
quasi-experimental design
type of experimental design that involves the participants in the experiment being separated into groups and each group is then matched by important variables (ie. sex, height)
matched groups
an experimental design where two groups are exposed to different experiemental conditions
independent-groups / between-subjects design
an experimental design were all participants take part in every condition.
within-groups design / within-subjects design
What are the two basic forms of an independent-group design
posttest-only design and pre-test/post-test
a basic experimental design where participants get randomly assigned to either receive the treatment or not, and the outcome is measured after treatment. type of independent-group experiment
posttest-only design
a basic experimental design where participants are initially given an assessment and are given another after receiving some type of treatment
pre-test / post-test design
What are the two basic forms of within-group designs?
repeated exposures design and concurrent measures design
an experiment where participants are measured on a dependent variable more than once after each level of exposure
repeated exposures design
an experiment where participants are exposed to all levels of an independent variable at roughly the same times and an attitudinal or behavioral preference is the dependent variable
concurrent measures design
when the order of treatments / sequence of tests impacts the results of the study
order effect
when the results of a study improve after repetition with the same participants
practice effect
when previous experience or knowledge may transfer to the next study
carryover effect
the small scale study done before a larger scale study
pilot study
A check that ensures the independent variable effectively created the intended dependent variable effects
manipulation checks
