Answer:
i. Target Group - University Fraternities
The focus of the statement is all University fraternities as the person making the statement did not limit the number of Fraternities included by saying some or most.
ii. Sample - Several Frat Brothers and a Fraternity
In coming to their conclusion, the author of the text used a sample of several frat brothers who were arrested at a frat-house party as well as a fraternity which was kicked off campus for violating underage drinking laws.
iii. Relevant property - Illegal Activity
The relevant property that all University Fraternities seem to have in come is illegal activity and the author gets this from the several frat brothers as well fraternity that were punished for actions contravening the law.