"With enough of a population size , you can check the effects of dozens of variables at once ."
"You can check the statistical relationship between dozens of variables , not the effects of them . For example if I correlated left hand strength with right hand strength across a billion individuals I would probably find a correlation of about 0.93 , however this relationship is not causal , cutting off one hand will not result in a 90 % strength reduction in the other . Correlational studies like this one can not determine cause and effect ."
"With enough of a population size , you can check the effects of dozens of variables at once ."
"You can check the statistical relationship between dozens of variables , not the effects of them"