1.Different ways of delivering surveys have different challenges. For example, the census delivers its survey by mail, but has difficulties collecting data on homeless people (who have no fixed address) and undocumented immigrants (who do not answer for fear of legal repercussions). List at least two practical difficulties involved in getting accurate results from each of these:

a.A telephone survey.

b.An online survey.

c.A survey done in person at a mall.