Exam LSAT Topic 2 Question 3 Discussion

Larry has purchased a device that the manufacturer claims will reduce the fuelconsumption in his car. After a month has passed, Larry determines that his mileagecurrently rests at 17 miles per gallon. Larry's best friend, Steve, owns the exact same makeand model car, and has calculated his mileage at 23 miles per gallon. Steve's car does nothave the device that Larry purchased one month ago. Larry then makes the conclusion thatthe manufacturer of the device's claim is not true.Which of the following statements would cause Larry's conclusion to be the weakest?