An energy drink company claims that its product increases students' memory levels. to support its claims, the company issues advertisements claiming that 8 out of 10 people (chosen randomly from across the country) who tried their product reported improved memory. the missing component in this study is a
a) control group b) sample group c) population d) test group

A) control group

Step-by-step explanation:

A control group is a group of participants who are used for comparing another group to in a test or experiment. It is composed of participants who do not receive the experimental treatment.

In the given situation an energy drink company claims that its product increases students' memory levels.

To support its claims, the company issues advertisements claiming that 8 out of 10 people (chosen randomly from across the country) who tried their product reported improved memory.

But they haven't compose a control group to compare the results for test.

Where is the diagram?

That is right sorry i was gonna answer but i already saw his