chapter 10 vocabulary Flashcards
A study based on data in which no manipulation f factors has been employed
Observational study
An observation study in which subjects are selected and the their previous conditions or behaviors are determined. Not based on random samples and usually focus on estimating differences differences between groups or associations between variables.
Retrospective study
An observation study in which subjects are followed to observe future outcomes. Because no treatments are deliberately applied. this study is not an experiment.
Prospective study
to manipulate factor levels to create treatment, randomly assigns subjects to those treatment levels , then compare those responses to groups across the treatment level.
experiment
to be valid,an experiment must assign experimental units to treatment groups at random.
random assignment
a variable whose levels are manipulated by the experimenter in an attempt to discover any effects that the factor levels may have response variable.
factor
a variable whose values are compared across different treatments. in a randomized experiment, large response, differences can be attributed to the effect of differences in a treatment level.
response
individuals on whom an experiment is performed. usually called subjects or participants when they are human.
experimental units
the specific values that the experimenter chooses for a factor are called the ______ of the factor
level
the process applied to randomly assigned experiment units. _______are the different levels of the factor
treatment
control, randomize, and replicate are all parts of this they are all principles of _______ ____
principles of an experimental design
all experimental units have an equal chance of receiving treatment
completely randomized design
when an observed difference is too large for us to believe that it is likely to have occurred by chance
statistically significant
the experimental units assigned to a baseline treatment level or placebo treatment. their responses provide a basis for comparison.
control group
when every individual in one group is blinded to their treatment
single blind design
when every individual in both groups are blinded from their treatment.
double blind design
a treatment known to have no effect administered so that all groups experience the same conditions.
placebo
the tendency of many human subjects to show a response even when administered a fake treatment
placebo effect
randomized, double blinded, comparative, and placebo- controlled: are qualities of what?
features of the best experiment
when there are pre-existing differences among the groups of experimental units, we isolate the differences so that we can see the effect of the treatment more clearly
blocking (design)
in a retrospective or prospective study or an experiment subjects who are similar in some ways, not under study are compared.
matching (design)
when the levels of one factor are associated with the levels of another factor in such a way that their effect cannot be separated.
confounding
when you make known the reason why something happened and the result of that reason
proving cause and effect
