Study Design In my study the null hypothesis is that Delta Airlines taxi out times = Southwest Airlines taxi out times as illustrated by the...
Study Design
In my study the null hypothesis is that Delta Airlines taxi out times = Southwest Airlines taxi out times as illustrated by the mathematical equation: 
.
µ1= Delta Airlines taxi out times.
µ2= Southwest Airlines taxi out times.
The alternate hypothesis is that Delta Airlines taxi out times are >Southwest Airlines taxi out times illustrated by the equation: 
.
I am using a two-sided/2 sample t-test that is right tailed.
The difference between Delta and Southwest taxi out times is being computed by subtracting from left – right.
Summary Statistics:
Summary statistics:
| Column | n | Mean | Variance | Std. dev. | Std. err. | Median | Range | Min | Max | Q1 | Q3 |
| Delta Taxi-Out | 100 | 8.81 | 9.5089899 | 3.083665 | 0.3083665 | 16 | 21 | 10 | |||
| Southwest Taxi-Out | 100 | 21.54 | 58.917576 | 7.6757785 | 0.76757785 | 20 | 42 | 51 | 17 | 25 |
Results Hypothesis test:
Hypothesis test results:
μ1: Mean of Delta Taxi-Out
μ2: Mean of Southwest Taxi-Out
μ1 - μ2: Difference between two means
H0: μ1 - μ2 = 0
HA: μ1 - μ2 > 0
(with pooled variances)
| Difference | Sample Diff. | Std. Err. | DF | T-Stat | P-value |
| μ1 - μ2 | -12.73 | 0.82720352 | 198 | -15.3892 |
Results confidence interval:
95% confidence interval results:
μ1: Mean of Delta Taxi-Out
μ2: Mean of Southwest Taxi-Out
μ1 - μ2: Difference between two means
(with pooled variances)
| Difference | Sample Diff. | Std. Err. | DF | L. Limit | U. Limit |
| μ1 - μ2 | -12.73 | 0.82720352 | 198 | -14.36126 | -11.09874 |
The T-test
Decision Rule.
Answer from Profstart:
We reject the null hypothesis if the P-Value is large i.e if the P-value is greater than the significance level or it lies in the critical region.
If P-value is smaller than the significance level, we do not reject the null hypothesis since the P-Value lies in the acceptance region.
In our case, the test statistic is -15.3892 and the corresponding P-value is 1. This clearly shows that the P-value lies in the critical/rejection region (The maximum value P can take is 1).
Hence, we reject the null hypothesis.
Decision: There is no enough evidence to show that Delta Air Lines will have a considerable amount more of taxi out time than Southwest Airlines.
