Question

In Hawaii shark attacks are very rare. Furthermore, about 55% of all shark attacks are serious, but not fatal.t You are scheduled to give a talk at a local scuba club in Honolulu and want to include a brief statistical profile regarding the most recent seven shark attacks, all of which were nonfatal. Let r be the number of nonfatal attacks out of a random sample of seven shark attacks (a) Make a histogram for the probability distribution of r 0 25 0.10 005 0.30 030 0 25 0.20 0.15 01s 0.10 0 05 (b) What is the probability all seven shark attacks are nonfatal? (Round your answer to three decimal places.) (c) What is the probability that five or more of the seven shark attacks are nonfatal? Round your answer to three decimal places.) (d) What is the expected number of nonfatal shark attacks out of the seven? What is the standard deviation of the r-probability distribution? (Round your answer to three decimal places.) Need Help?

Answer 1

Binomial distribution (n=7, p=0.45)
	f(x)	F(x)	1 - F(x)
x	Pr[X = x]	Pr[X ≤ x]	Pr[X > x]
0	0.0152	0.0152	0.9848
1	0.0872	0.1024	0.8976
2	0.2140	0.3164	0.6836
3	0.2918	0.6083	0.3917
4	0.2388	0.8471	0.1529
5	0.1172	0.9643	0.0357
6	0.0320	0.9963	0.0037
7	0.0037	1.0000	-0.0000

b)

0.0037

c)

P(X>5) = 0.1529

d)

E(x) = 7*0.45 = 3.15

Stand dev = (n*p*q)^0.5 = (7*0.45*0.55)^0.5 = 1.316