Fallacy of Hasty Generalization
It is a Fallacy we commit when we draw conclusions about all the persons or things in a given class on the basis of our knowledge about only one or few members of that class.[1] This is converse of Fallacy of Accident when we presume what is true in general is also true in an exceptional case.
Example: A stole money from B`s purse therefore A is a habitual criminal. This is hasty generalization.
[1] Copi Irving and Cohen Carl (2009), Introduction to Logic, Pearson Education Inc. and Dorling Kindersley, South Asia, pg 148