Being a social science, economics deals with whole of the society. Therefore, instead of individual behaviour, collective economic behaviour is examined in the economics. in other words, it is analyzed how a nation can satisfy its unlimited wants with limited resources. The study of collective behaviour help us to formulate some laws which further help to solve individual economic problems.
Economics is a social science (A man is social when he is living in a society) so If we study the human behaviour individually we can neither solve economic problems nor we can derive economic laws, because the attitude, sentiments of different people are different and as a result we cannot benefit from the subject, e.g. when price of commodity increases normally people purchase smaller amount of that commodity, but there may some who will purchase more due to snob. Therefore, in economics we study collective human behaviour instead of individual human behaviour.