In: Statistics and Probability
Complaints about weekday airline flights not being on time average about 15.17 complaints per month at airports in small U. S. cities. The local airport is proud to advertise that its average monthly on-time performance is superior to the national monthly average for small city airports. Since June 2003, a random sample of nine months reveals that the number of complaints regarding weekday flights not being on time at the local airport were: 9 10 12 13 14 15 15 16 17 Using the 0.05 significance level, does the data justify the local airport's claim?
The null hypothesis?
the alternate hypothesis?
What is the correct test statistic?
Will the upper tail, lower tail, or both tails be used?
What is (are) the critical values: (Fill in the blank with the correct number to 4 decimal places.)
What is the sample mean? (Fill in the blank with the correct number to 4 decimal places.)
What is the population mean, mu? (Fill in the blank with the correct number to 4 decimal places.)
Will you use the population standard deviation or the sample standard deviation?
What number will you use for the standard deviation? (Fill in the blank with the correct number to 4 decimal places.)
What is the computed value of the test statistic? (Fill in the blank with the correct number to 4 decimal places.)
does the test statistic fall in the critical region or the rejection region:
Is your decision not to reject or to reject the null hypothesis
Is your decision in favor of the null hypothesis or the alternate hypothesis:
The correct statistical conclusion is:
Using the 0.05 level of significance, does the data justify the local airport’s claim? Explain your answer
The null hypothesis?
Ho: μ ≥ 15.17
the alternate hypothesis?
Ha: μ < 15.17
What is the correct test statistic?
SE = s/√n = 2.6977/√9 = 0.899233333
t = (x-bar - μ)/SE = (13.44 - 15.17)/0.899233333333333 = -1.923861067
Will the upper tail, lower tail, or both tails be used?
Only lower tail will be used
What is (are) the critical values: (Fill in the blank with the correct number to 4 decimal places.)
-1.8595
What is the sample mean? (Fill in the blank with the correct number to 4 decimal places.)
13.44
What is the population mean, mu? (Fill in the blank with the correct number to 4 decimal places.)
15.17
Will you use the population standard deviation or the sample standard deviation?
Sample standard deviation
What number will you use for the standard deviation? (Fill in the blank with the correct number to 4 decimal places.)
2.6977
What is the computed value of the test statistic? (Fill in the blank with the correct number to 4 decimal places.)
-1.9239
Does the test statistic fall in the critical region or the rejection region:
Yes
Is your decision not to reject or to reject the null hypothesis
Reject the Ho
Yes, data justify the local airport’s claim.