THE OWNER OF A GASOLINE STATION WANTS TO STUDY GASOLINE PURCHASING HABITS OF MOTORISTS AT HIS STATION. HE SELECTS A RANDOM SAMPLE OF 60 MOTORISTS DURING A CERTAIN WEEK , WITH THE FOLLOWING RESULTS: THE AMOUNT PURCHASED WAS ASAMPLEMEAN= 11.3 GALLONS; S = 3.1 GALLONS. ELEVEN MOTORISTS PURCHASED PREMIUM-GRADE GASOLINE.

FIND: AT THE 0.05 LEVEL OF SIGNIFICANCE , IS THERE EVIDENCE THAT THE POPULATION MEAN PURCHASED WAS DIFFERENT FROM 10 GALLONS ?