Case I.
The Western Europa Airline claims that the travel time from Durblin, Ireland to Madrid, Spain
with a mean of 220 minutes and a standard deviation of 10 minutes. Newly appointed complia
40 travels that the mean travel time was 216 minutes. At the 5% significance level, is the com
1. State the hypotheses. Specifically, what is the null hypothesis and what is the alternative h
H_0: mu=220 (i.e. the travel time is 220 min.)
This is twotailed test.
2. Which test statistic are you going to use? In other words, identify the distribution of the tes
Standard Normal, Zscore, since the population standard deviation is known.
3. Calculate the critical values.
1.96
4. State your decision rule.
Reject the null, if z_obs>CV; otherwise, fail to reject the null.
5. Compute the test statistic.
z_obs=(X_barmu)/std.error=(216220)/(10/sqrt(40))=
2.53
6. Applying the decision rule, what can you conclude?
Since the absolute value of z_obs, which is 2.5298, greater than the absolute value of CV, which is 1
is 220 minutes at 5% significance level.
7. What is the Pvalue ?
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 Spring '11
 Camp
 Economics, Statistics, Normal Distribution, Standard Deviation, Null hypothesis, Statistical hypothesis testing

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