9)

When bonding teeth, orthodontists must maintain a dry field. A new bonding adhesive has been developed to eliminate the necessity of a dry field. However, there is concern that the new bonding adhesive is not as strong as the current standard, a composite adhesive. Tests on a sample of 11 extracted teeth bonded with the new adhesive resulted in a mean breaking strength (after 24 hours) of x = 4.83 Mpa and a standard deviation of s = 0.45 Mpa. Orthodontists want to know if the true mean breaking strength is less than 5.45 Mpa, the mean breaking strength of the composite adhesive. C. . . A. Ho: H = 5.45 VS. Ha: H 5.45 O E. Ho: H= 4.83 VS. Ha: H - 2.764 O C. t 3.169 OF. t> 2.764 O G. t> - 3.169 OH. t