Suppose you want to know the average amount of money spent by the fans attending opening day for the Cleveland Indians baseball season. You get permission from the team's management to conduct a survey at the stadium, but they will not allow you to bother the fans in the club seating or box seats (the most expensive seating). Using a random number generator, you select 500 seats from the rest of the stadium. During the game, you ask the fans in those seats how much they spent that day. Describe how undercoverage might lead to bias in this study. Explain the likely direction of the bias.