Probability and its Measurement: Statistics and Probability theory constitutes a branch of mathematics for dealing with uncertainty. Probability theory provides a basis for the science of statistical inference from data.
The probability of a particular event can be defined as the ratio of the number of favourable cases for the particular event to the total number of cases both favourable and unfavourable to this particular event. As an example, consider the event of enumerating the persons who had the attack of smallpox in a community. The probability of coming across a person with the history of the attack of smallpox is the ratio of the number of persons with the history of attack of smallpox to the total number of persons in the community.
As another example, if the probability of a patient leaving the hospital against medical advice during a year’s time is to be computed, then this will be the ratio of the number of patients who have left the hospital against medical advice during a year’s time to the total number of patients admitted to the hospital during that year.
