Question 129973: I already submitted this question. The missing data is Apha=.05. Please help me. I am totally lost and need your help. Thank you again
1. The EPA is concerned about the quality of drinking water served on airline flights. A sample of 158 flights yielded poor quality water on 20 flights. At alpha=.05, does this indicate that more than 10% of flights have poor-quality water?
2. According to the sample, 12.66% (20/158) of the flights served poor-quality water. Can you simply report to the EPA that more than 10% of all airline flights serve poor-quality water? Why or why not?
3. If an error occurred, what type of error was it?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! 1. The EPA is concerned about the quality of drinking water served on airline flights.
A sample of 158 flights yielded poor quality water on 20 flights. At alpha=.05, does this indicate that more than 10% of flights have poor-quality water?
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Ho: p = 0.10
Ha: p > 0.10 (right-tail test with alpha = 5%)
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Critical value = 1.645
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p-hat = 20/158 = 0.1266
Test Statistic:
z(0.1266) = (0.1266-0.10)/sqrt(0.1*0.9/158)= 46.69777...
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Since the test statistic is greater than the critical value
reject Ho. There is strong statistical evidence that the
proportion pf poor quality is not 10%
2. According to the sample, 12.66% (20/158) of the flights served poor-quality water. Can you simply report to the EPA that more than 10% of all airline flights serve poor-quality water? Why or why not?
Since this is a test of Ho that p = 10% you can only report that the
test shows significant statistical evidence that the proportion is not 10%.
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3. If an error occurred, what type of error was it?
Type I; rejecting Ho when in fact it is true.
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Cheers,
Stan H.
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