the manufacturer of the X-15 steel-belted truck tire claims that the mean mileage the tire can be driven before the tread wears out is 60,000 miles. the standard deviation is 5,000 miles. the crosset truck company bought 48 tires and found that the mean mileage for their truck is 59,500 miles. is crosset's experience different from the claimed by the manufacturer at the .05 level of significance?|||Ho: mu=60,000
Ha: mu鈮?0,000
z = (x-mu)/(s/sqrt(n)) = (59,500 - 60,000)/(5,000/sqrt(48)) = 0.6928
z critical (alpha = 0.05) = 1.96
rejection zone: |z calculated| %26gt; 1.96
calculated z is not in the rejection zone, so we do not reject Ho. Crosset's experience is statistically not different than manufacturer's claim.
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment