Q4. An oil prospecting firm hits oil or gas on 10% of its drillings. If the firm drills two wells, the four possible simple events and three of their associated probabilities are as given in the accompanying table. Find the probability that the company will hit oil or gas (a) on the first drilling and miss on the second. (b) on at least one of the two drillings. Simple Outcome of Outcome of Event First Drilling Second Drilling Probability E1 Hit (oil or gas) Hit (oil or gas) 0.01 E2 Hit Miss ? E3 Miss Hit 0.09 E4 Miss Miss 0.81 Q3 (8 points) Q3. A survey classified a large number of adults according to whether they were diag- nosed as needing eyeglasses to correct their reading vision and whether they use eyeglasses when reading. The proportions falling into the four resulting categories are given in the following table: Use Eyeglasses for Reading Needs glasses Yes No Yes 0.44 0.14 No 0.02 0.40 If a single adult is selected from the large group, find the probabilities of the events defined below. The adult (a) needs glasses. (b) needs glasses but does not use them. (c) uses glasses whether the glasses are needed or not.