A hypothesis is a tentative explanation for an observation, phenomenon, or scientific problem that can be tested by further investigation. It is a statement, not a question, and is usually based on some prior knowledge or preliminary observations. Key characteristics include:

1. Testable:

   It can be tested through experiments, observations, or analysis of data.

2. Falsifiable:

   It must be possible to demonstrate that the hypothesis is not true through observation or experimentation.

3. Predictive:

   It should make predictions about what will happen in certain circumstances.

4. Clear and Concise:

   It should be easily understood and specific.

A well-formed hypothesis often includes an independent variable (the factor being manipulated) and a dependent variable (the factor being measured). Hypotheses can be proven or disproven.