Thread:User talk:WaitingforGodot/Quick question for you.../reply (13)

I answered question #3 below- you can't just compare countries because you aren't conrolling for variables. I also proposed a solution for #1 that I've seen printed in various places, including that CDC website and the American Acadamy of Pediatrics- here's the CDC link, which includes links to dozens of studies and meta-analyses on the subject that you might want to look through.