Hasty Generalization Fallacy
“After walking through this town for 10 minutes, I have seen several children but no adults. I guess all residents of this town are children!”
You make a hasty generalization when you jump to a conclusion without enough evidence. In other words, it means drawing an inference with too small of a sample size.
Hasty generalizations can lead to stereotypes. For example, if someone meets two people from a country and they are both rude, a hasty generalization might lead them to conclude that everyone from that country is rude.
Inductive reasoning, however, is not necessarily a fallacy and can be very useful. Inductive reasoning means using specific examples to draw general conclusions. For example, if medical professionals conclude, after working with many patients, that certain symptoms are likely to indicate a certain disease, this is inductive reasoning and it is not a fallacy.
Imagine you have a friend who undergoes a medical procedure, and the procedure causes no side effects. It would be a hasty generalization (and also the anecdotal fallacy) to conclude from this information alone that the medication causes no side effects.
But if a study had been conducted on the effects of this treatment on a large group of people and none of them had experienced side-effects, it would be rational to conclude that the medication is unlikely to produce side-effects. It is important to note that when we use inductive reasoning we can only talk about probabilities, not about certainties.