Question

How do you do these questions? The same distributional assumptions will be made. This article from the Guardian in 2015 reports on two shark attacks in two days.

Answer 1

Step-by-step explanation:

October 4th is the 277th day of the year, so the average number of shark attacks in 2015 in a two-day period is:

29 / 277 × 2 = 0.21

The probability of 2 attacks in a two-day period is:

P(x; μ) = e^(-μ) (μˣ) / x!

P(2; 0.21) = e^(-0.21) (0.21²) / 2!

P(2; 0.21) = 0.0178

The probability of at least 2 attacks is:

P(≥2; 0.21) = 1 − P(0; 0.21) − P(1; 0.21)

P(≥2; 0.21) = 1 − e^(-0.21) (0.21⁰) / 0! − e^(-0.21) (0.21¹) / 1!

P(≥2; 0.21) = 0.0186