Hi, need to submit a 500 words essay on the topic Conceptual math. This involves

Hi, need to submit a 500 words essay on the topic Conceptual math.
This involves sorting the population into like-groups. Then people are picked for survey from each group randomly. This involves grouping on basis of personal traits mostly. For example, you sort people with respect to the baseball club they support and then select people from the groups at random without any bias