Type of Attack If one person is randomly selected, what is the likelihood that he or she was victimized by a stranger, given that a robbery victim is selected?
A) 389/505
B) 389/1,118
C) 389/2,000
D) 1,234/2,000

Question

Type of Attack  If one person is randomly selected, what is the likelihood that he or she was victimized by a stranger, given that a robbery victim is selected?
A) 389/505 
B) 389/1,118 
C) 389/2,000 
D) 1,234/2,000

Quizplus · Accepted Answer

The question requires the calculation of conditional probability, i.e., the probability of a stranger being the perpetrator given that the victim is a robbery victim. Let A be the event that the victim is victimized by a stranger, and let B be the event that the victim is a robbery victim. The probability of A given B is P(A|B) = P(A and B)/P(B), where P(A and B) is the probability of a stranger committing a robbery, and P(B) is the probability of a robbery victim being selected. From the table, P(A and B) = 389 and P(B) = 505. Hence, P(A|B) = 389/505.

Type of Attack If One Person Is Randomly Selected