Lets say you randomly select 7 flights from 4 different airl

Let’s say you randomly select 7 flights from 4 different airlines to examine if there are significant differences in on-time performance among the airlines. The dependent variable is the number of minutes that a flight is late (so a negative number means the flight is early, and a zero value means the flight was on-time). Here are the (hypothetical) data:

North-South Airline

Southern Skies

Central West

Happy Flier

1

25

15

-10

2

10

8

-8

1

15

5

-3

0

5

24

0

-10

-4

8

-24

2

0

10

-4

-3

14

8

-2

Use SPSS to produce an appropriate graph that shows the mean performance of each airline. Copy and paste the graph from the SPSS output below. (2 points)

State the null and alternative hypotheses using symbols and/or words. (1 point)

Using SPSS, determine whether there is a significant difference in on-time performance among the different airlines (alpha = .05), be sure to include the SPSS output for the ANOVA summary table. (3 points)

State your conclusion and include a mean and SD table in APA style. (4 points)

Which airlines (if any) have significant (alpha = .05) pair-wise differences in on-time performance? To fully answer this, you will need to conduct a Tukey’s HSD test as a post hoc test using SPSS (be sure to include the output below). Write the conclusions of this post hoc test in APA style. Additionally, provide clear statements in plain English about the significant differences in on-time performance among the airlines (10 pts.)

Solution

Sol)

H0: All the means of four groups are equal

Ha: All the means of four groups are not equal.

level of significance: 5%

Test Statistic:

We use Anova one way

From SPSS output

Conclusion: Since p value=0.585 and alpha=0.05, p value > alpha, we accept the null hypothesis.

Hence all the four groups means are equal.

Now Tukey’s HSD test