ABSTRACT
This book began with an overview of the context for statistics-kinds of research and variables, relationships among variables, generalizations from a sample to a population, and so forth. Generalizing from a sample to a population is not a trivial matter. Any sample, even a representative one that was drawn without bias, will provide data that will differ somewhat from the data that we could have gotten from a different sample. For example, think about randomly sampling 150 young adults who joined the military last year. We want to measure height, and to control for the extraneous variable of gender, we sample only men. We could compute the mean height of these 150 men. Question: If we draw another random sample of 150 other men who joined the military last year, will we get the same mean height?
