Bart runs a food truck in front of a multi-story office building. He wants to know which type of sandwiches his customers prefer, grilled or plain. He randomly surveyed a few of his friends who have eaten at his food truck and recorded the results. Friends Preferring Grilled Sandwiches Friends Preferring Plain Sandwiches
15 5

In this case, the population consists of
and the sample consists of
.

Based on the results, it can be concluded that
. The results would have been more accurate if Bart had surveyed
.