When studying any kind of population — people or cells — averaging is a useful, if flawed, form of measurement. According to the US Census Bureau, the average American household size in 2010 was 2.59. Of course, there are no homes with exactly 2.59 people. By inspecting each house individually, one would see some homes occupied by a single individual, and others by large families. These extremes get lost when values are averaged over a population.