This document discusses statistical hypothesis testing and statistical inferences. It notes that statistical hypothesis testing is one of the most important applications of probability theory in statistics. This allows researchers to make decisions about accepting or rejecting hypotheses based on sample data. The process of decision making through hypothesis testing involves multiple steps, including drawing a representative sample, collecting relevant data, applying statistical rules to test hypotheses, and making a decision based on results. Statistical inferences aim to estimate unknown population parameters through sampling and probability theory plays a key role in this process and in decision making more broadly.