Question

Isle Royale, an island in Lake Superior, has provided an important study site of wolves and their prey. Of special interest is the study of the number of moose killed by wolves. In the period from 1958 to 1974, there were 296 moose deaths identified as wolf kills. The age distribution of the kills is as follows. Age of Moose in Years Number Killed by Wolves Calf (0.5 yr) 1-5 6-10 11-15 16-20 110 45 75 60 6 (a) For each age group, compute the probability that a moose in that age group is killed by a wolf. (Round your answers to three decimal places.) 0.5 Incorrect: Your answer is incorrect. 1-5 6-10 11-15 16-20 (b) Consider all ages in a class equal to the class midpoint. Find the expected age of a moose killed by a wolf and the standard deviation of the ages. (Round your answers to two decimal places.) μ = σ =

Answer 1

			freq/total freq
x	mid point(x)	freq	p(x)
0.5	0.5	110	0.371622
1-5	3	45	0.152027
6-10	8	75	0.253378
11-15	13	60	0.202703
16-20	18	6	0.02027
	total	296	1

=

x	P(x)	x*P(x)	x^2*P(x)
0.5	0.371622	0.185811	0.092905
3	0.152027	0.456081	1.368243
8	0.253378	2.027027	16.21622
13	0.202703	2.635135	34.25676
18	0.02027	0.364865	6.567568
sum	1	5.668919	58.50169

=5.67

=5.13