Formulation of a hypothesis may not be necessary in

Formulation of a hypothesis may not be necessary in fact-finding historical research, which gathers and records past facts.

Such descriptive reconstruction of events proceeds without a relationship to be tested.

Survey studies commonly test hypotheses about how measured variables relate.

Experimental studies exist to test a hypothesis by manipulating an independent variable.

Explanatory studies seek causes and therefore depend on hypotheses about relationships.

Historical and purely descriptive work often begins from questions rather than hypotheses.