Analisa conducted an experiment to determine if watching different types of commercials would affect a person's pulse. her hypothesis was that pulse rate would change with different types of commercials. each person watched seven different commercials, averaging 30 seconds each. each person's pulse was taken before the commercial and then after each commercial. based on her experiment analisa concluded that a person's pulse rate changed when the person watched different types of commercials. which component is missing from analisa's experiment? a. a question b. a hypothesis c. a control group d. a description of the experiment

C. a control group

Explanation:

A control group is the group which is used in an experiment. It is kept as a standard or benchmark for the comparison of the changes that occur in an experimental variables.

In the given experiment no control group is used. That is all the seven groups were exposed to different types of commercial there was no group which was not exposed any of the commercial. Hence, the validity of the experiment is doubtful.

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