system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: what exactly is the deal behind when they say “ 9 out of 10 doctors approve this medication”?
gpt
Biased sample fallacy.

The doctors asked most likely had some financial incentive, loyalty of misinformation on the product and/or company.

Also, they may have asked hundreds of sample sets of ten until they got the highest percentage.

Also, if a premium product, they may have asked doctors in wealthy area or practice, whereas they would have got a different result in less wealthy areas.

It’s a con trick.