Answers
- Here, we perform two sample t test to test mean delivery time of local pizzas and national chain pizzas
We want to test,
: Mean delivery time of local pizzas and national chain pizzas is same
Vs: Mean delivery time of local pizzas is less than national chain pizzas
i.e.Vs
We perform test in minitab as Stat>Basic Statistics>2-Sample t test
Two-Sample T-Test and CI: Local, National
Two-sample T for Local vs National
N Mean StDev SE Mean
Local 16 16.45 3.41 0.85
National 16 19.38 2.86 0.71
Difference = mu Local - mu National
Estimate for difference: -2.93
95% upper bound for difference: -1.04
T-Test of difference = 0 (vs <): T-Value = -2.64 P-Value = 0.007 DF = 29
Decision: Here, P-Value = 0.007 < level of significance 0.05
There is enough evidence to reject .
Conclusion: We may conclude that mean delivery time of local pizzas is less than national chain pizzas
- Here, we perform f test to test variation in delivery time for local pizzas and national chain pizzas
We want to test,
: Variation between delivery time of local pizzas and national chain pizzas is same
Vs: Variation between delivery time of local pizzas and national chain pizzas is not same
i.e.Vs
We perform test in minitab as Stat>Basic Statistics>2-variances
Test for Equal Variances
Level1 Local
Level2 National
ConfLvl 95.0000
Bonferroni confidence intervals for standard deviations
Lower Sigma Upper N Factor Levels
2.41547 3.40705 5.64873 16 Local
2.02666 2.85862 4.73946 16 National
F-Test (normal distribution)
Test Statistic: 1.421
P-Value : 0.505
Levene's Test (any continuous distribution)
Test Statistic: 0.654
P-Value : 0.425
Decision: Here, P-Value = 0.425> level of significance 0.05
We fail to reject .
Conclusion: We may conclude that variation between delivery time of local pizzas and national chain pizzas is same