This document discusses the concept of a hypothesis. It defines a hypothesis as a tentative statement about the solution to a research problem or as conjectural statement about the relationship between two or more variables. The document outlines the importance of hypotheses in guiding focused inquiry and preventing blind research. It also describes characteristics of a good hypothesis, sources of hypotheses, different types of hypotheses including universal, existential, descriptive, explanatory, and null hypotheses. Finally, it discusses potential problems in formulating hypotheses and types of errors in testing hypotheses.