Appeal to popularity

An appeal to popularity, also called argumentum ad populum (Latin for "appeal to the people"), is a logical fallacy. It happens when someone tries to argue that something is right because lots of people believe in it.Austin Cline. Argumentum ad Populum 

An example is saying "many people buy extended warranties, therefore we should buy one for our new computer".

Related pages
 Argumentum ad hominem

References

Category:Logical fallacies