The sample data below represent the number of late and on ti

The sample data below represent the number of late and on time flights for the Delta, United and US Airways (Bureau of Transportation Statistics, March 2012). Formulate the hypotheses for a test that will determine if the population proportion of late flights is the same for all three airlines. Choose correct answer from above choice Conduct the hypothesis test with a .05 level of significance. What is the p-value? What is your conclusion? Compute the sample proportion of late flights for each airline. What is the overall proportion of late flights for the three airlines? Round your answer to three decimal places. The overall proportion of late flights for the three airlines is

Solution

a. H0: p1=p2=p3

Ha : Atleast one pi is different for i = 1,2,3.

b.DF = (r - 1) * (c - 1) = (2 - 1) * (3 - 1) = 2

The P-value is the probability that a chi-square statistic having 2 degrees of freedom is more extreme than 2.1173.

P - value = 0.3469

If the p-value is greater than the -level then we fail to reject the null hypothesis.

here P - value = 0.3469 > 0.05 so we reject null hypothesis.

c.

sample proportion of late flight for Delta = 39/146 =0.2671

sample proportion of late flight for United= 51/146 =0.3493

sample proportion of late flight for US Airways = 56/146 =0.3836

Overall proportion of late flights for the three airlines = 146/1000 =0.146

		Airline
Flight	Delta	United	US Aiways	Total
Late	39	51	56	146
On Time	261	249	344	854
Total	300	300	400	1000