Ex post facto is a quasi-experimental study examining how an independent variable, present prior to the study in the participants, affects a dependent variable. A quasi-experimental study is one where participants are not randomly assigned. Case study refers to a qualitative, detailed study combining both objective and subjective data of an individual or a small group of individuals. Case study research focuses narrowly on exploration and description of a phenomenon to achieve an in-depth understanding. Survey is a research method used for collecting data from a pre-defmed group of respondents to gain information and insights on various topics of interest. Surveys have a variety of purposes and can be carried out in many ways depending on the methodology chosen and the objectives to be achieved. Experimental research (see ans. 6)