Question

A pilot study to evaluate the serum alpha tocopherol levels (serum vitamin E) was conducted to evaluate the toxicity among 14people who regularly take vitamin-E supplements. The vitamin E levels for the 15 participants are listed below. If the level of alpha tocopherol in the general population 875μg/dL, conduct a hypothesis test to determine if those who take supplements have significantly different levels of serum alpha tocopherol with alpha = 5% and the sample standard deviation is 479.92μg/dL.

660 2030 1150 800 1605 1240 810 1990 1135 655 1150 1600 980 1200 920

1. What hypothesis test is appropriate to answer this research question?

2. What is the alternative hypothesis?

3. What is the critical value?

4. What is the sample mean?

5. What is the test statistic rounding to two decimal places?

6. True or False: Fail to reject H0as the test statistic does not fall within the rejection region.

7. Suppose the investigator of the pilot study wants to expand to a larger study to make sure 80% power is achieved. What sample size is needed to detect a difference in means of 75 given the standard deviation of 479.92?

8. What sample size is needed to ensure adequate power based on question 7 if it is suspected there will be 15% attrition?

Answer 1

The sample mean is

1:

Since population standard deviation is unknown so t test will be sued.

(2-6)

7: