Respuesta :
A researcher carries out an experiment to demonstrate a fact or make a
discovery, or gain insight into a subject.
The element that distinguishes an observational study from a randomized
experiment is D. In an observational study a control group is never used,
whereas in a randomized experiment a control group is always used.
Reasons:
An observational study is a study focused on observing an impact of a
cause such as a treatment, test, factor of risk, while not making effort to
control or change the subjects of the impact. The researcher does not
make attempt in affecting the subjects of the experiment but measures the
effect.
Therefore;
- A randomized experiment does not use a control groups used
A randomized experiment, involves dividing the sample under study into
two;
- A group that receives the treatment, known as the treatment group
- A control group that will not be subject to the treatment
Therefore;
- A treatment group is always used in a randomized experiment
The correct option is D. In an observational study a control group is never
used, whereas in a randomized experiment a control group is always used.
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