Question

Michelle Grace is a frequent traveler between Australia and New Zealand. For the past month, she wrote down the flight times on three different airlines. The results are :

Alpha

51

51   

52

51

47

60

62

80

Bravo

50

52

52

49

58

52

40

Charlie

52

55

60

42

42

a.Use the 0.05 significance level to check if there is a difference in the mean flight times among the three airlines

b.Is there different between Alpha and Charlie (use 0.05 significant level)

Answer 1

Answer A.

Null Hypothesis, Ho: There is no significant difference in the mean flight times among the three airlines, i.e.

  

Alternative Hypothesis, Ha: There exists at least one airline for which the mean flight time is significantly different from others i.e for at least one

Test Statistics: Under Ho,

where k = number of groups = 3 and,

n = number of observations = 20

Calculations:

Treatment Groups	ni		si
Alpha	8	56.75	10.6603
Bravo	7	50.4286	5.4116
Charlie	5	50.2	8.0125

So,

and

Decision:

Since, p-value = 0.281 > , so we fail to reject the Null Hypothesis at 5% level of significance.

Conclusion:

There is no significant difference in the mean flight times among the three airlines, i.e.

  

Answer B.

Since, we have concluded in part A. So, this implies that there is no significant difference between Alpha and Charlie.