What is a hypothesis?

A hypothesis is a testable prediction, which means it is formulated based on observations and prior knowledge, and it can be empirically tested through experimentation or observation. This characteristic sets a hypothesis apart from other concepts in science. It serves as a starting point for scientific investigation, allowing researchers to design experiments to confirm or refute it.

A well-formed hypothesis is specific and measurable, which enables scientists to quantify the results of their experiments and make informed conclusions. This focus on testability is fundamental to the scientific method, where hypotheses are tested and either supported or rejected based on experimental data.

While other options encompass different aspects of scientific inquiry, they do not define a hypothesis accurately. A firmly established theory represents a much broader and well-supported scientific concept, whereas a mere description of an event lacks the predictive component necessary for a hypothesis. A control group is an essential part of experimental design but does not fit the definition of a hypothesis itself.