2nd Question Explanation
Going to Silcon Valley is like going to the Canteen of NYU? can you explain how you assumed that this sample is not random? I mean you can ask 50 people randomly at the canteen as well so..?
Hi Abdelrahman, Hope you are doing well.
The question itself says "You go to Silicon Valley and visit 200 start-ups in a random manner"
Visiting 200 start-ups in a silicon valley alone is a representative sample, but visiting 200 start-ups in a random manner cannot be considered as representative.
Picking from NYU canteen is considerably representative, coz they are considering only students from canteen as a whole.
Have a great learning!