Sometimes i­t may not possible to observe the outcomes of events; therefore, the researcher may assign a probability to an event. In subjective probability approach, the researcher assigns a suitable value as the probability of the event. Therefore, a personal judgment comes in to play to assign the probability. Thi­s approach is not favorable method to assign probability, but sometimes i­f there’s no previous knowledge on the subject then the researcher may assign a subjective probability as a starting point.