We need information to make decisions. And when our decisions involve random processes ... information can become a little problematic. Sometimes we are forced to take measurements of different outcomes of a random process. We call these 'samples.' You may have done something like this in high school when you measured the heights of your fellow students to plot a histogram to get some idea of the random nature of student height. But how many student heights do you need to get to be comfortable you know enough about all student heights? We call the number of students whose height you measure the 'sample size.' Do you need to learn more about working out the sample size for something you are working on?