Answer to Question #331423 in Statistics and Probability for erika miguel

Question

Directions: Read the problems below and do what is asked. Write your answers on a separate sheet of paper. 

2. The average zone of inhibition (in mm) for mouthwash L as tested by the medical technology students has been known to be 9mm. A random sample of 10 mouthwash L was tested and the test yielded an average zone of inhibition of 7.5mm with a variance of 25 mm. Is there enough reason to believe that the anti-bacterial property of the mouthwash has decreased? Test the hypothesis that the average zone of inhibition of the mouthwash is no less than 9mm using 0.05 level of significance.

A. State the hypotheses. 

B. Determine the test statistic to use. 

C. Determine the level of significance, critical value, and the decision rule. 

D. Compute the value of the test statistic. 

E. Make a decision. 

F. Draw a conclusion.