The ABC corporation claims that its new gasoline additive for passenger cars will enhance the mileage per tankfull of gasoline if a can of their product is added to a full tank of gasoline. Five vehicles were tested, yielding the following results (miles per tankfull):
|
Vehicle
|
1
|
2
|
3
|
4
|
5
|
|
Before additive
|
370
|
385
|
375
|
380
|
378
|
|
After additive
|
387
|
397
|
380
|
392
|
389
|
Find a 95% confidence interval for the difference in the means of these two data sets.