When copying an angle, what is the first short-term goal?

Plz me plz i need and plz delte this after answer

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 .

Me. i can't figure out this question. give an explanation too. .