Question

Two fuel additives are being tested to determine their effect on gasoline mileage. Seven cars were tested with additive 1 and nine cars were tested with additive 2. The following data show the miles per gallon obtained with the two additives.

Additive 1	Additive 2
17.3	17.7
17.4	18.8
20.1	21.3
15.7	20.0
18.2	22.1
17.6	19.7
17.5	18.8
	19.7
	21.2

Use α = 0.05 and the MWW test to see whether there is a significant difference between gasoline mileage for the two additives.

Find the value of the test statistic:

W = ?

Find the p-value. (Round your answer to four decimal places.):

p-value = ?

Answer 1

	Additive 1 ( X )		Additive 2 ( Y )
	17.3	0.1488	17.7	4.9382
	17.4	0.0816	18.8	1.2593
	20.1	5.8288	21.3	1.8983
	15.7	3.943	20	0.0061
	18.2	0.2645	22.1	4.7428
	17.6	0.0073	19.7	0.0494
	17.5	0.0345	18.8	1.2593
			19.7	0.0494
			21.2	1.6328
Total	123.8	10.3085	179.3	15.8356

Mean

Standard deviation

Mean

Standard deviation

To Test :-

H0 :-  

H1 :-  

Test Statistic :-


t = -3.2784

Test Criteria :-
Reject null hypothesis if


DF = 13


Result :- Reject Null Hypothesis

Decision based on P value
P - value = P ( t > 3.2784 ) = 0.006
Reject null hypothesis if P value < level of significance
P - value = 0.006 < 0.05 ,hence we reject null hypothesis
Conclusion :- Reject null hypothesis

There is sufficient evidence to support the claim that there is a significant difference between gasoline mileage for the two additives.