This economics education publication focuses on the U.S. stock market and the risk and uncertainty that an individual faces when investing in the market. The material explains that risk and uncertainty relate to the same underlying concept randomness. It defines and discusses both concepts and notes that although risk is quantifiable, uncertainty is not, rather arising from imperfect knowledge about the way the world behaves. The document also contains a question and answer (Q&A) section which discusses the Federal Open Market Committee (FOMC), the U.S. Federal Reserve Bank's chief body for monetary policymaking. (BT)