Question 1091473: In the past, it has taken an express mail company an average of 2 days to deliver packages. After hiring a consulting firm, they want to know if delivery has improved. Let µ= average number of days needed to deliver a package after hiring a consulting firm. The company wants to test the following:
A sample of 100 packages yields xbar = 1.8 and s = 1.5. For α = 0.05, what do you conclude?
Found 2 solutions by stanbon, nazee:
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! In the past, it has taken an express mail company an average of 2 days to deliver packages. After hiring a consulting firm, they want to know if delivery has improved. Let µ= average number of days needed to deliver a package after hiring a consulting firm. The company wants to test the following:
A sample of 100 packages yields xbar = 1.8 and s = 1.5. For α = 0.05, what do you conclude?
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Ho: u = 2
Ha: u < 2 (claim)
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Sample mean:: x-bar = 1.8
Test Statistic:: z(1.8) = (1.8-2)/1.5 = -0.1333
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p-value = P(z < -0.1333) = normalcdf(-100,-0.1333) = 0.45
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Since the p-value is greater than 0.05, fail to reject Ho.
Conclusion:: The test results support the claim that delivery time has improved.
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Cheers,
Stan H.
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Answer by nazee(1) (Show Source):
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