The accuracy of a census report on a city in southern California was questioned by some...

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The accuracy of a census report on a city in southern Californiawas questioned by some government officials. A random sample of1215 people living in the city was used to check the report, andthe results are shown below.

EthnicOriginCensusPercentSampleResult
Black10%        139        
Asian3%        35        
Anglo38%        469        
Latino/Latina41%        503        
Native American6%        56        
All others2%        13        

Using a 1% level of significance, test the claim that the censusdistribution and the sample distribution agree.

(a) What is the level of significance?


State the null and alternate hypotheses.

H0: The distributions are the same.
H1: The distributions aredifferent.H0: The distributions aredifferent.
H1: The distributions aredifferent.    H0: Thedistributions are the same.
H1: The distributions are thesame.H0: The distributions are different.
H1: The distributions are the same.


(b) Find the value of the chi-square statistic for the sample.(Round the expected frequencies to at least three decimal places.Round the test statistic to three decimal places.)


Are all the expected frequencies greater than 5?

YesNo    


What sampling distribution will you use?

uniformnormal    binomialchi-squareStudent'st


What are the degrees of freedom?


(c) Estimate the P-value of the sample test statistic.

P-value > 0.1000.050 < P-value <0.100    0.025 < P-value <0.0500.010 < P-value < 0.0250.005 <P-value < 0.010P-value < 0.005


(d) Based on your answers in parts (a) to (c), will you reject orfail to reject the null hypothesis that the population fits thespecified distribution of categories?

Since the P-value > α, we fail to rejectthe null hypothesis.Since the P-value > α, wereject the null hypothesis.    Since theP-value ≤ α, we reject the null hypothesis.Sincethe P-value ≤ α, we fail to reject the nullhypothesis.


(e) Interpret your conclusion in the context of theapplication.

At the 1% level of significance, the evidence is sufficient toconclude that census distribution and the ethnic origindistribution of city residents are different.At the 1% level ofsignificance, the evidence is insufficient to conclude that censusdistribution and the ethnic origin distribution of city residentsare different.    

Answer & Explanation Solved by verified expert
3.5 Ratings (356 Votes)

a) level of significance =0.01

H0: The distributions are the same.
H1: The distributions are different

b)

Applying chi square test:

           relative observed Expected residual Chi square
category frequency Oi Ei=total*p R2i=(Oi-Ei)/√Ei R2i=(Oi-Ei)2/Ei
Black 0.10 139.00 121.50 1.59 2.521
Asian 0.03 35.00 36.45 -0.24 0.058
Anglo 0.38 469.00 461.70 0.34 0.115
Latino/Latina 0.41 503.00 498.15 0.22 0.047
Native American 0.06 56.00 72.90 -1.98 3.918
All others 0.02 13.00 24.30 -2.29 5.255
total 1.000 1215 1215 11.913

value of the chi-square statistic =11.913

Are all the expected frequencies greater than 5? Yes

What sampling distribution will you use? Chi square

degrees of freedom =5

c) 0.025 < P-value < 0.05

d)

Since the P-value > α, we fail to reject the null hypothesis.

e)

At the 1% level of significance, the evidence is insufficient to conclude that census distribution and the ethnic origin distribution of city residents are different.    


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