Question

# Two computer stores recorded the number of computers sold in a week along with the sizes...

Two computer stores recorded the number of computers sold in a week along with the sizes of their hard drives. At , test the claim that the distribution of hard drives and the store where the computers were bought are not related. Number of computers 20 GB drive 40 GB drive 80 GB drive 160 GB drive Store 1 14 10 13 11 Store 2 117 40 26 10

null hypothesis: Ho:distribution of hard drives and the store where the computers were bought are not related.

alternate hypothesis:Ha:distribution of hard drives and the store where the computers were bought are related

 degree of freedom(df) =(rows-1)*(columns-1)= 3
 for 3 df and 0.05 level of signifcance critical region       χ2= 7.815
 Applying chi square test of independence:
 Observed Oi 20 GB 40 GB 80 GB 160 GB store 1 14 10 13 11 store 2 117 40 26 10 Total 131 50 39 21 Expected Ei=Σrow*Σcolumn/Σtotal 20 GB 40 GB 80 GB 160 GB store 1 26.09 9.96 7.77 4.18 store 2 104.91 40.04 31.23 16.82 Total 131 50 39 21 chi square    χ2 =(Oi-Ei)2/Ei 20 GB 40 GB 80 GB 160 GB store 1 5.6034 0.0002 3.5246 11.1121 store 2 1.3936 0.0000 0.8766 2.7636 Total 6.997 0.000 4.401 13.876

test statistic χ2=13.876

Decision:as test statistic is in rejection region we reject null hypothesis

Conclusion: we have sufficient evidence to conclude that distribution of hard drives and the store where the computers were bought are related

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