Question

4) All students are expected to use library resources. You want to know if frequencies of library visit differ by student classification. Here are the observed and expected data. Conduct chi square goodness of fit to test if observed score differ from expected score.

	Freshman	Sophomore	Junior	Senior
Observed	30	20	20	30
Expected	20	25	25	30

Answer 1

H0:no differences in  observed score and expected score

H1:.observed score differ from expected score.

alpha=0.05

In the below table

O-observed frequency

E-expected frequency

O	E	O-E	(O-E)^2	(O-E)^2/E
30	20	10	100	5
20	25	-5	25	1
20	25	-5	25	1
30	30	0	0	0
			CHI SQ TEST STATISTIC	7

degrees of freedom=k-1=4-1=3

p value=0.071898

p>0.05

Do not reject null hypothesis

Accept null hypothesis.

no differences in  observed score and expected score

there is no sufficient evidence at 5% level of significance to support the claim that

observed score differ from expected score.