Primary data is information collected through original research by the marketer or researcher themselves. Primary data is used to test hypotheses, which are tentative statements or assumptions about the relationship between variables or the outcome of an experiment. Testing hypotheses helps to validate or invalidate the assumptions and predictions made by the marketer or researcher, and to measure the effectiveness and impact of their product or service.
Reference:
Primary Data - Types, Methods and Examples: This article from Research Method defines primary data, explains its types and methods, and provides some examples of primary data collection and analysis.
[Hypothesis Testing]: This article from the Scaled Agile Framework describes the concept and process of hypothesis testing, and how it helps to evaluate the value proposition and assumptions of a product or service using experiments and feedback.