Primary research involves collecting data directly through methods like surveys, observation, and experiments to test hypotheses or evaluate groups. Secondary research uses data collected by others for administrative purposes, including government statistics and documents. Quantitative data is numerical, while qualitative data cannot be expressed numerically and includes nominal variables. Market research gathers data about markets, products, customers, and competitors to understand characteristics and needs. Production research focuses on how products are made. Design research originally studied design processes but now also examines contexts of design and research-based practices.