Demographic information refers to the statistics that describe a population and can be used to divide that population into different groups. Examples of demographic information include age, gender, race, income, marital status, employment status, nationality and political preference.
Demographic information is often gathered about the subjects of scientific research or as a part of surveys related to marketing and public opinion. Using the demographic information helps the testers understand how the data is different for certain groups of the population. For example, a scientist conducting an experiment might want to know if males react differently than females, or a company launching a new product might want to know how American opinions differ from European opinions.