Question 1/2 : a) Aclass in advareed physics is cornamin. following table shows phy. at random from this cless ii) Find the probability that the student received A grade. iii) Find the probability that the student received A grade or he is senior. iii) Find the probability that the student received A grade, given that he is senior. b) A sample is selected from one of two populations, S1 and S2, with probabilities P(S1)=0.7 and P(S2)=0.3. If the sample has been selected from S1, the probability of observing an event A is P(A/S1)=0.2. Similarly, if the sample has been selected from S2, the probability of observing A is P(A/S2)=0.4 i) If a sample is randomly selected from one of the two populations, what is the probability that event A occurs? ii) If the sample is randomly selected and event A is observed, what is the probability that the sample was selected from population S2