Quantitative research can be applied to quantifiable facets of a problem; its findings can suggest solutions to what, where and when type questions. It includes methods of inference, experiment and simulation. Inference based methods seeks to establish characteristics and relationships. Experimental research is conducted under controlled settings where researcher can manipulate variables and note down observations. Simulation relates to modelling techniques. Qualitative research is used for non-quantifiable phenomenon and is widely used social science, psychology and market research to understand the reason and context that facilitate the occurrence of such phenomenon, that is, it seeks to answer the how and why type questions.  Qualitative method includes interviews, observations, documents, reports, open ended questions, word association tests, sentence completion tests and story completion tests.