Question 1105652: Assuming. X is normally distributed on average he was stuck for u=20 minutes a random selection of five days showed the delay to have a mean =15.2 minutes with a sample deviation of 6.3 minutes does this mean the delay is now shorter use significant level .05
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Assuming. X is normally distributed on average he was stuck for u=20 minutes.
A random selection of five days showed the delay to have a mean =15.2 minutes with a sample deviation of 6.3 minutes. Does this mean the delay is now shorter?
Use significant level .05.
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Ho: u >= 20
Ha: u < 20 (claim)
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Since sample deviation = 6.3, std = 6.3*sqrt(5) = 14.09
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z(15.2) = (15.2-20)/14.09 = -0.34
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p-value = P(z < -0.34) = normalcdf(-100,-0.34) = 0.63
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Conclusion:: Since the p-value is greater than 0.05, fail
to reject Ho.
Conclusion:: The test results do not support the claim that
u < 20 sec.
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Cheers,
Stan H.
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