Which is an example of a controlled experiment?
a subject who is not getting treatment
a study where investigators decide who will be in a treatment group and who will not
a study in which the subjects assign themselves to different groups
a study on the effects of smoking
a process outside the control of the investigators
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Carlos Rodriguez <firstname.lastname@example.org>
This problem was contributed by a student in Elementary Statistics. It is offered as it is with no warranty of any kind
Last modified: Wed May 13 12:29:11 EDT 1998