Overgeneralization
Overgeneralization is a fallacy occurring when a statistic about a particular population is asserted to hold among members of a group for which the original population is not a representative sample.
For example, suppose 100% of apples are observed to be red in summer. The assertion "All apples are red" would be an instance of overgeneralization because the original statistic was true only of a specific subset of apples (those in summer), which is not expected to representative of the population of apples as a whole.
A real-world example of the overgeneralization fallacy can be observed as an artifact of modern polling techniques, which prohibit calling cell phones for over-the-phone political polls. As young people are more likely than other demographic groups to have only a cell phone, rather than also having a conventional "landline" phone, young people are more likely to be liberal, and young people who do not own a landline phone are even more likely to be liberal than their demographic as a whole, such polls effectively exclude many voters who are more likely to be liberal.
Thus, a poll examining the voting preferences of young people using this technique could not claim to be representative of young peoples' true voting preferences as a whole without overgeneralizing, because the sample used is not representative of the population as a whole.
Overgeneralization often occurs when information is passed through nontechnical sources, in particular mass media.
Read more about this topic: Misuse Of Statistics, Types of Misuse