Question: View the 20,000 people in the donations database on the companion site as a random sample from a much larger group of potential donors. Determine whether or not the amount donated in response to the current mailing (named "Donation" in the database), on average, is enough to cover the per-person cost (assumed to be 38 cents) of preparing materials and mailing them. In particular, can you conclude that it was significantly worthwhile to solicit a donation from this group?