Basic level stats plzz help mee?

4. Samplings: Students in Class. Suppose you are assigned the number 1, and each of the other students in your statistics class calls out consecutive numbers until each person in class his or her number. Explain how you could get a random sample of four students from your statistics class.


(a) Explain why the first four students walking into the classroom would not necessarily form a random sample.


(b) Explain why four students coming in late would not necessarily form a random sample.


(c) Explain why four students sitting in the back row would not necessarily form a random sample.


(d) Explain why the four tallest students would not necessarily form a random sample.

Basic level stats plzz help mee?
You could get a random sample by taking every 7th person (or other relatively large number).





a) People entering together may be friends and therefore not random since they chose each other, probably because they have similarities.


b), c) and d) also have obvious things in common, so they are not a RANDOM sample.
Reply:For a sample to be picked randomly the basic question you need to answer is " Does everybody have the same chance of being picked EVERY TIME you choose someone". If the answer is yes then your sample has been picked randomly.


To answer your first question just put a piece of paper in a hat with everyones number on it and pick out one at a time until you have 4.


(a) Not random because once you decide to pick your sample this way everyone except the first four have ZERO chance of being picked.


All the other options (b), (c) and (d) you can pose a similar argument to that in (a)

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