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

1. The records of SCA Registrar show that the average final grade in Mathematics for

STEM students is 91 with a standard deviation of 10. A group of student-researchers

found out that the average final grade of 37 randomly selected STEM students in

Mathematics is no longer 91. Use 0.05 level of significance to test the hypothesis.

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.

2. The average zone of inhibition (in mm) for mouthwash H as tested by medical technology

students has been known to be 9mm. A random sample of 10 mouthwash H was tested

and the test yielded an average zone of inhibition of 7.5 mm with a variance of 25mm. Is

there enough reason to believe that the antibacterial 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.