Handbook of Biological Statistics by John H. McDonald"One of the main goals of statistical hypothesis testing is to estimate the P value, which is the probability of obtaining the observed results, or something more extreme, if the null hypothesis were true. If the observed results are unlikely under the null hypothesis, your reject the null hypothesis. Alternatives to this "frequentist" approach to statistics include Bayesian statistics and estimation of effect sizes and confidence intervals." - Summary from author's website.
Introduction to Epidemiology
Study Guide to Epidemiology and Biostatistics; Hebel and McCarter (2012)