Question 662203: In a certain industry, about 15 percent of the workers showed some signs of ill effects due to radiation. After management had claimed that improvements had been made, 140 workers were tested and 19 experienced some ill effects due to radiation. Does this result support management's claim? Use alpha=0.05
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! In a certain industry, about 15 percent of the workers showed some signs of ill effects due to radiation. After management had claimed that improvements had been made, 140 workers were tested and 19 experienced some ill effects due to radiation. Does this result support management's claim? Use alpha=0.05
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Ho: p >= 0.15
Ha: p < 0.15 (claim that things have improved)
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p-hat = 19/140 = 0.1357
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z(0.1357) = (0.1357-0.15)/sqrt[0.15*0.85/sqrt(140)] = -0.0143/0.0302 = -0.4739
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p-value = P(z < -0.4739) = 0.3178
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Since the p-value is greater than 5%, fail to reject Ho.
The test does not support management's claim.
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Cheers,
Stan H.
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