Collecting the data The class will be divided into an even number of teams of at least two students each, and the teams will be separated into two groups.

Within the first group, each team measures out a half-cup of shells and counts the number of shells. The process here is that one person pours shells into the half-cup measure until the person thinks that it is full.

The second person then counts the number of shells and records it without informing the first person of this number. Each team repeats the experiment five times and computes the mean and the standard deviation for its measurements.

In the second group, students use a transparent plastic measure. One person in the team pours shells into the one-cup measure until the person thinks it has reached the half-cup mark by holding the cup in the air and checking the level. The second person counts the number of shells and records it. Again, each team repeats the experiment five times and computes the mean and the standard deviation.