Question

RecommendationsSkill plansMathLevel L* X.15 Find probabilities using the addition rule UKVYou have prizes to reveal! Go toA college professor asked his Psychology students to complete a personality test. He paidspecial attention to his students' career goals and their greatest fears.The probability that a student wants to be a doctor is 0.35, the probability that a student hasa fear of snakes is 0.63, and the probability that a student wants to be a doctor or has a fearof snakes is 0.92.What is the probability that a randomly chosen student wants to be a doctor and has a fear ofsnakes?W.Submit

Answer 1

Notice that the probability of student wanting to be a doctor is 0.35 (35%), and the probability that a student fears snakes is 0.63 (63%).

But notice that the probability of a student wanting to be a doctor OR fearing snakes is 0.92 (92%)

Notice as well that the addition of the probability of being a doctor PLUS the probability of fearing snakes is NOT 92%, but 35% + 63% = 98%.

This means that there is an overlap in those two sets of 98% minus 92% = 6%

Then the probability of a student wanting to be a doctor AND fearing snakes must be that remaining 6% (0r 0.06 in decimal form)

This may be seen better in a Venn Diagram. If you want I can draw it for illustration. You will see there that the two sets are NOT disjunt.