How significant is the relationship between ethnic groups and cultural identity? How important is cultural identity?

Culture influences personal identity because this gives you the label for the group that you belong in. Within culture you will find language, customs, mores, group beliefs, and how to interact with people who are like yourself. Humans are social animals and culture is the glue that holds groups of humans together.

buying socks and buying shoes are independent events.

answer; researchers typically cannot control people's sexual behaviors as would be necessary in an experiment;