Many species of cuckoos are brood parasites They lay their e

Many species of cuckoos are brood parasites. They lay their eggs in the nests of other species. The following data are for the lengths (mm) of cuckoo eggs in a random sample of nests from two different host species.

wren: 19.8, 22.1, 21.5, 20.9, 22, 21, 22.3, 21, 20.3, 20.9, 22, 20, 20.8, 21.2, 21

house sparrow: 22, 23.9, 20.9, 23.8, 25, 24, 21.7, 23.8, 22.8, 23.1, 23.1, 23.5, 23, 23

Question 7 (1 point)

Calculate a 95% confidence interval for the mean length of cuckoo eggs for each of the host species.

Question 7 options:

wren (20.3, 22.0), house sparrow (22.0, 23.9)

wren (20.7, 21.5), house sparrow (22.6, 23.7)

wren (19.6, 22.6), house sparrow (21.0, 25.2)

wren (20.9, 21.3), house sparrow (22.8, 23.4)

Question 8 (1 point)

Which of the following claims is supported by the data?

Question 8 options:

On average eggs in wren nests are more variable in size than eggs in house sparrow nests

On average eggs in wren nests are smaller than eggs in house sparrow nests

Although slightly different in the sample, the average size of eggs in wren nests is plausibly about the same as eggs in house sparrow nests

On average eggs in wren nests and house sparrow nests are about the same size

	wren (20.3, 22.0), house sparrow (22.0, 23.9)
	wren (20.7, 21.5), house sparrow (22.6, 23.7)
	wren (19.6, 22.6), house sparrow (21.0, 25.2)
	wren (20.9, 21.3), house sparrow (22.8, 23.4)

Many species of cuckoos are brood parasites. They lay their eggs in the nests of other species. The following data are for the lengths (mm) of cuckoo eggs in a random sample of nests from two different host species. wren: 19.8, 22.1, 21.5, 20.9, 22, 21, 22.3, 21, 20.3, 20.9, 22, 20, 20.8, 21.2, 21 house sparrow: 22, 23.9, 20.9, 23.8, 25, 24, 21.7, 23.8, 22.8, 23.1, 23.1, 23.5, 23, 23 Question 7 (1 point) Question 8 Unsaved Which of the following claims is supported by the data? Question 8 options: On average eggs in wren nests are more variable in size than eggs in house sparrow nests On average eggs in wren nests are smaller than eggs in house sparrow nests Although slightly different in the sample, the average size of eggs in wren nests is plausibly about the same as eggs in house sparrow nests On average eggs in wren nests and house sparrow nests are about the same size Question 7 Unsaved Calculate a 95% confidence interval for the mean length of cuckoo eggs for each of the host species. Question 7 options: wren (20.3, 22.0), house sparrow (22.0, 23.9) wren (20.7, 21.5), house sparrow (22.6, 23.7) wren (19.6, 22.6), house sparrow (21.0, 25.2) wren (20.9, 21.3), house sparrow (22.8, 23.4) Question 8 (1 point)

Solution

(7) wren: n1=15, xbar1=21.12, s1=0.7542262

The degree of freedom =n-1=15-1=14

Given a=0.05, t(0.025, df=14) =2.14 (from standard normal table)

So the lower bound is

xbar - t*s/vn =21.12 - 2.14*0.7542262/sqrt(15) =20.70326

So the upper bound is

xbar + t*s/vn =21.12 + 2.14*0.7542262/sqrt(15) =21.53674

house sparrow: n2=14, xbar2=23.11429, s2=1.049437

The degree of freedom =n-1=14-1=13

t(0.025, df=13) =2.16 (from student t table)

So the lower bound is

xbar - t*s/vn =23.11429 - 2.16*1.049437/sqrt(14) =22.50847

So the upper bound is

xbar + t*s/vn =23.11429 + 2.16*1.049437/sqrt(14) =23.72011

Answer: wren (20.7, 21.5), house sparrow (22.6, 23.7)

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(8)On average eggs in wren nests are smaller than eggs in house sparrow nests