In this lecture, we continue our discussion of statistically rigorous methods for input modeling in simulation of stochastic systems. We first cover the basics of hypothesis testing, including a review of type-I error (alpha), p-values, and how they relate to critical values for goodness-of-fit tests (like Chi-squared and KS). We then review Q-Q and P-P probability plots to identify candidate families for input models from collected data. Then we discuss how maximum likelihood estimation (MLE) provides a bridge from summary statistics to mathematically justifiable choices for parameter values of the distributions we have chosen. Next time, we will discuss Chi-square testing and KS testing as applied to general probability distributions (i.e., not just as tests for uniformity).