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UW Madison wants to know what the average salary of their alumni is. They have 30,000 members in their alumni association. Each person is sent a survey. From the 30,000 questionaires, 8,500 are randomly selected and averaged. Based on 8,500 responses selected, UW-Madison concluded that the annual salary of its alumni was around $75,000 per year.
Is this a random sampling? If not, what type of sampling is it?
Yes!