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 9 extracted teeth bonded with the new adhesive resulted in a mean breaking strength? (after 24? hours) of x overbar =4.57 Mpa and a standard deviation of s =0.34Mpa. Orthodontists want to know if the true mean breaking strength is less than 5.18 ?Mpa, the mean breaking strength of the composite adhesive.
- Set up the null and alternative hypotheses for the test.
- Next find the rejection region for the test using a =0.01.
- Compute the test statistic. t= (round to two decimals)
- Give the appropriate conclusion for the test.
- What conditions are required for the test results to be? valid?