Statıstıcs Iı Deneme Sınavı Sorusu #1058141
A chocolate factory is examining the sales of their new brand chocolates in two nearby cities. The number of chocolates sold in city 1 is 300 (n1) and 120 of the chocolates were their new brand chocolates. On the other hand, in the city 2, 240(n2) of the sold chocalates, 150 of them were their new brand chocolates. What is the test statistics? ([(1/300) + (1/240)] can be assumed to be equal to 0.25)
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-2.9 |
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-1.9 |
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-1.6 |
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-1.3 |
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-0.9 |
n1 =300, x1 = 120 then p1 = x1/n1= 120/300= 0.4
n2 =240, x1 = 150 then p2 = x2/n2= 150/240= 0.625
p = (x1 + x2)/(n1 + n2) = (120 + 150)/(240 + 300) =0.5
Then, z-test is used to test the difference between two proportions p1 and p2 and the test statistic is as follows: The numarator is 0.4 - 0.625 = -0.225.
0.5x(1-0.5)=0.25, [(1/300)+(1/600)] is assumed to be equal to 0.25 therefore the denominator is 0.25. This yields to z = -0.225/0.25 = -0.9
The answer is E.
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