Question

Question 61 pts

There are two types of sneetches, the star-bellied sneetch (S. astra) and the plain sneetch (S. simplex). Professor O. B. Servant counted sightings of these sneetches, identified each sneetch he saw, and classified their location into the three types: Ground, Tree, and Lake. The number of sightings are shown in the table below:

	S. astra	S. simplex
Ground	60	35
Tree	34	41
Lake	28	42

Professor O.B. Servant would like to know if the habitat use is independent of the types of sneetches.

Find the expected frequency for S. astra on ground if the habitat use is independent of the types.

Round your answer to the nearest 0.01.

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Question 71 pts

Continue the previous problem.

Calculate the test statistic X2 for testing the independence of the two variables.

Round your answer to the nearest 0.01.

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Question 81 pts

Continue the previous problem.

Find the number of degrees of freedom for the test statistic X2 for testing the independence of the two variables.

Round your answer to the nearest 0.01.

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Question 91 pts

Continue the previous problem.

Find the p-value for testing the independence of the two variables.

Round your answer to the nearest 0.01.

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Question 101 pts

Continue the previous problem.

Based on the p-value, is the habitat use independent of type?

Cannot tell.

Yes

No

Answer 1

61)xpected frequency for S. astra on ground =row total*column total/grand total=48.29

71)

applying chi square test:

Expected	Ei=?row*?column/?total	S. Astra	S.Simplex	Total
	Ground	48.2917	46.708	95
	tree	38.125	36.875	75
	lake	35.583	34.417	70
	Total	122	118	240
chi square	=(Oi-Ei)2/Ei	S. Astra	S.Simplex	Total
	Ground	2.839	2.935	5.774
	tree	0.446	0.461	0.908
	lake	1.616	1.671	3.287
	Total	4.901	5.067	9.968

test statistic X2 =9.97

81_)

number of degrees of freedom =(row-1)*(column-1)=(3-1)*(2-1)=2

91)

p value =0.01

101)