Chapter 3 Vocabs
Terms
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- dropouts
- subjects who begin the experiment but do not complete it
- block
- group of experimental subjects that are known before the experiment to be similar in some way that is expected to affect the response to the treatments.
- institutional review board
- reviews all planned studies in advance in order to protect the subjects from possible harm.
- response variable
- variable that measures an outcome or result of a study
- randomized comparative experiment
- an experiment that compares just two treatments.
- treatment
- specific experimental condition applied to the subjects. If an experiment has several explanatory variables, a treatment is a combination of specific values of these variables.
- placebo or placebo effect
- dummy treatment with no active ingredients.
- informed consent
- all individuals who are sujects in a study must give their informed consent before data are collected.
- completely randomized
- experimental design, all the experimental subjects are allocated at random among all the treatments.
- confounded
- two variables are confounded if their effects on a response variable cannot be distinguished from each other. The confounded variables may be either explanatory variables or lurking variables.
- statistically significant
- an observed effect so large that it would rarely occur by chance
- double-blind experiment
- neither the subjects nor the people who work with them know which treatment each subject is receiving.
- block design
- random assignment of subjects to treatments is carried out separately within each block.
- matched pairs design
- common design that combines matching with randomization
- anonymity
- different than confidentiality. It means that subjects are anonymous
- nonadherers
- subjects who participate but don't follow the experimental treatment
- explanatory variable
- variable that we think explains or causes changes in the response variables
- lurking variable
- variable that has an important effect on the relationship among the variable in a study but is not one of the explanatory variables studied.
- confidential
- all individual data must be kept confidential. Only statistical summaries for groups of subjects may be made public.
- principles of experimental design
- 1) control: the effects of lurking variables on the response, most simply by comparing two or more treatments...2) randomize: use impersonal chance to assign subjects to treatments...3) use enough subjects: in each group to reduce chance variation in the results.