Question

# We want to compare the average gas mileage of American-made cars vs. Japanese-made cars. The claim...

We want to compare the average gas mileage of American-made cars vs. Japanese-made cars.
The claim is that the Japanese cars and American cars do not get the same gas mileage.
Use the list data below to test the hypothesis that the Japanese cars and American cars do not get the same gas mileage.
The American cars are in list1 and the Japanese cars in list2 below
We do not know whether the mileages are normally distributed or not, but their variances are equal.
Use alpha = 0.05
USA - Japan

18 - 24

15 27

18 27

16 25

17 31

15 35

14 24

14 19

14 28

15 23

15 27

14 20

15 22

14 18

22 20

18 31

21 32

21 31

10 32

10 24

11 26

9 29

28 24

25 24

19 33

16 33

17 32

19 28

18 19

14 32

14 34

14 26

14 30

12 22

13 22

13 33

18 39

22 36

19 28

18 27

23 21

26 24

25 30

20 34

21 32

13 38

14 37

15 30

14 31

17 37

11 32

13 47

12 41

13 45

15 34

13 33

13 24

14 32

22 39

28 35

13 32

14 37

13 38

14 34

15 34

12 32

13 33

13 32

14 25

13 24

12 37

13 31

18 36

16 36

18 34

18 38

23 32

11 38

12 32

One Tail or Two? - [ Choose ]CUFTR Ho8.478638e-25-17.3377130682-12.62059186.5Reject HoOne5.439851e-30Two3.267637e-38

Test Statistic = [ Choose ]CUFTR Ho8.478638e-25-17.3377130682-12.62059186.5Reject HoOne5.439851e-30Two3.267637e-38

p = [ Choose ]CUFTR Ho8.478638e-25-17.3377130682-12.62059186.5Reject HoOne5.439851e-30Two3.267637e-38

Decision = [ Choose ]CUFTR Ho8.478638e-25-17.3377130682-12.62059186.5Reject HoOne5.439851e-30Two3.267637e-38

Enter CU here - [ Choose ]CUFTR Ho8.478638e-25-17.3377130682-12.62059186.5Reject HoOne5.439851e-30Two3.267637e-38

using minitab>stat>basic stat>two sample t

we have

Two-Sample T-Test and CI: USA, Japan

Two-sample T for USA vs Japan

N Mean StDev SE Mean
USA 79 16.03 4.20 0.47
Japan 79 30.61 5.97 0.67

Difference = μ (USA) - μ (Japan)
Estimate for difference: -14.582
95% CI for difference: (-16.204, -12.961)
T-Test of difference = 0 (vs ≠): T-Value = -17.76 P-Value = 0.000 DF = 156
Both use Pooled StDev = 5.1595

here claim :Japanese cars and American cars do not get the same gas mileage.

this is two tail test

Test Statistic = -17.76

p =0.000

Decision = since p value is less than 0.05 so we rejct Ho and conclude that Japanese cars and American cars do not get the same gas mileage.