If a life time probability to develop a lung cancer is 25% than what are odds of deeveloping lung cancer in life time is -

Ans. is 'b' i.e., 1 : 3 Odds It is another measure for the occurence of a outcome or event. It is the chance of frequency of occurrence of a characteristic relative to its non-occurrence, i.e., it is the ratio of occurrence. Odds Vs probability The probability is a propoion, i.e., it is the number of times a given outcome occurs divided by all the occurrences. If we take a sample of blood from a patient five times, and the sample is positive one time, then the probability is 1 in 5 or 0.20. On the other hand, the odds is a ratio, i.e., it is the number of times a given outcome occurs divided by the number of times that specific outcome does not occur. With same blood sample example, the odds of a positive sample is = No. of positive slide/No of negative slide = 1/4. Example If the probability of occurence of a cancer is 0.25 (25%). In otherword the nonoccurence of cancer will be = 1 - 0.25 = 0.75 (75%).