Researchers at the University of Iowa College of Medicine ...

[frankwu]

Researchers at the University of Iowa College of Medicine reported that a test showed those who smoked seven or more marijuana joints per week had lower math scores than non-marijuana users. A related headline says New study confirms too much pot impairs brain. Explain why the headline is misleading.

Question 2

Researchers at the University of Iowa College of Medicine reported that a test showed those who smoked seven or more marijuana joints per week had lower math scores than non-marijuana users. A related headline says New study confirms too much pot impairs brain. Explain why these results must have been based on an observational study, and not an experiment.

[JYan]

Answer to Question 1

IT IMPLIES THAT THERE IS A CAUSAL CONNECTION BETWEEN SMOKING MARIJUANA AND BRAIN FUNCTION. IT COULD BE THE CASE THAT PEOPLE WHO CHOOSE TO SMOKE MARIJUANA ARE THOSE WHO WOULD SCORE LOWER ON THE TESTS ANYWAY.

Answer to Question 2

PEOPLE CANNOT BE RANDOMLY ASSIGNED TO EITHER SMOKE MARIJUANA OR NOT.

[frankwu]

Gracias!

[Jsherida]

Thanks for the timely response, appreciate it