Statistical methods for inferential statistics are available for single, two, and multiple parameters/populations/variables. The complexity of the statistical methods increases with the increase in the number of parameters/variables/populations of interests. In this module, inferential statistics on single and double parameters will be discussed. Statistical methods involving multiple parameters of interests will be discussed in the rest of the modules. We will start with the simplest statistical methods, which include the inferential statistics on a single population. The flow chart in Figure 1 provides a guideline in choosing the appropriate statistical method for a single population.