When do you think about probability? Do you think about games of chance, shuffling cards, rolling dice, the probability of winning a lottery? Or do you think about events in daily life, the probability that you will need your umbrella today, the probability you will make it to an appointment on time when traffic is heavy? Using statistics depends critically on a basic understanding of probability. We need concepts from probability theory to know, for instance, what it means to draw a random sample, or how to estimate how likely it is that we might observe a particular value of a variable or statistic.

In this module, we begin using inferential statistics to test hypotheses. We use the z-test, which compares a sample mean with a population mean, to introduce the concept of statistical significance and the steps involved in determining whether a result is statistically significant.

This module provides a variety of information and tools from the American Psychological Association (APA) that will help inspire you as you complete your coursework and plan your career goals. Explore APA resources on various psychological issues and scholarly research and writing; a list of sites providing valuable resources on diversity, equity, and inclusion in psychology education and in the professional community; resources on a career in psychology; and links to career opportunities at the APA.