Samples and Populations

Abstract

Very often the data we see is a small part of the data we could have seen. The data we could have observed, if we could have seen everything, is the populationpopulation. I will write populations like random variables with capital letters to emphasize we don’t actually know the whole population. The data we actually have is the samplesample(lower case, as usual). We would like to know the population meanpopulation mean, which we write popmeanX. We must estimate this using the sample.