The International Shark Attack File maintained by the Florid

The International Shark Attack File, maintained by the Florida Museum of Natural History, is a compilation of all known shark attacks around the globe from the mid 1500s to the present. Following is a contingency table providing a cross-classification of worldwide reported shark attacks during the 1990s, by country and lethality of attack. Find P(L_1), the probability that a reported shark attack in the 1990s was fatal. Find P(C_4), the probability that a reported shark attack in the 1990s took place in the US. Find P(C_4 & L_1), the probability that a reported shark attack in the 1990s took place in the US was fatal. Find P(C_4 | L_1), the probability that a reported shark attack in the 1990s took place in the US given that it was fatal.

Solution

A)

P(L1) = 70/540 = 0.12962963 [ANSWER]

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b)

P(C4) = 249/540 = 0.461111111 [ANSWER]

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c)

P(C4 and L1) = 5/540 = 0.009259259 [ANSWER]

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d)

P(C4|L1) = 5/70 = 0.071428571 [ANSWER]