Direction: Identify the appropriate form of test-statistic to be used in the following situations. Select whether it is T-TEST, Z-TEST, or CENTRAL LIMIT THEOREM.

11. A labor union president claims that the mean age of the employees in a certain company is 38 with a standard deviation of 6. A random sample of 20 employees from the same company has a mean age of 36 and standard deviation of 5. Test at 5% significance level that the mean age of the employees is not 38. * 12. A teacher wants to find out if his teaching strategy is effective. A sample of 55 students took a 100-point examination and the average is 80 with a standard deviation of 7. Test at 10% significance level that the average of the students is greater than 75 which is the standard passing score. * 13. The Health Department reports that the systolic blood pressure for ages 18- 30 years has a mean of 125. In a study of health workers, a sample of 200 workers has a systolic blood pressure average of 120 with a standard deviation of 4. Do the data suggest that the average systolic blood pressure is lower than 125 at 1% significance level? * 14. A pharmaceutical company says that the efficacy rate of their medicine is 90% and the standard deviation is 2%. A sample of 50 volunteers from a city reveals that the efficacy rate is 88% with a standard deviation of 3%. At 1% significance level, check the veracity of the statement of the company. * 15. The average income of a customer service representative is P 23,000. A survey was conducted among 15 customer service representatives in the city and the mean is 24,000 and the standard deviation is P 5,000. Is there a significant difference between the population mean and sample mean at 5% significance level?

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