Statistical inference is the process of drawing general conclusions from specific studies. This section presents the fundamental concepts that provide the basis for statistical inference and examines the effect of endpoint definition, patient selection, and study design (especially randomized trials versus observational studies) on the validity of the general conclusions. This section also introduces descriptive statistics and measures of change, as investigators frequently summarize change from baseline or from control using the difference or percent change without using objective criteria for choosing the best measure of change. This section will show how graphical methods can assist in choosing between differences, percent change, log ratios, and other measures so that the resulting measure is as independent of baseline as possible. Section 1 will also present an overview of statistical resources available at Vanderbilt.