Question

Delta Airlines is trying to determine if pilots are deliberately slowing down during a labor dispute. They know that their all their flights have a mean late time of 12.8 minutes with a standard deviation of 5.8 minutes. They took a random sample of 36 flights during the dispute and found they were 15.1 minutes late on average. Using a significance level of 0.05, is there any evidence to back their claim that the pilots are slowing down?

Answer 1

Solution :

= 15.8

=12..8

s =5.8

n = 36

This is the two tailed test .

The null and alternative hypothesis is ,

H0 :    = 12.8

Ha :     12.8

Test statistic = t

= ( - ) / s / n

= (15.1 -12.8) /5.8 / 36

= 2.379

Test statistic = t =  2.379

P-value =0.0229

= 0.05  

P-value <

0.0229 < 0.05

Reject the null hypothesis .

There is sufficient evidence to suggest that