Wk 13 - HOMEWORK ASSIGNMENT #9

1. The level of various substances in the blood of kidney dialysis patients is of concern. A researcher did blood tests on a dialysis patient on six consecutive clinic visits. One variable measured was the level of phosphate in the blood. The data on this one patient, in milligrams of phosphate per deciliter (mg/dl) of blood, are:

5.6 5.1 4.6 4.8 5.7 6.4

1. (10 pts) The normal range of values for blood phosphate level is 2.6 to 4.8 mg/dl. Is there evidence that the patient's mean level in fact falls above 4.8?

• Use Hypothesis Test Template.
• Calculate and stdev from the raw data given.

1. (4 pts) Given your conclusion, are you at risk of making a Type I error or a Type II error? Provide your answer in the context of the problem.

1. (4 pts) Report a one-sided 95% confidence interval for the mean blood phosphate level.

1. (4 pts) What sample size would you recommend, if it is important to detect and treat the elevated average phosphate level of 5.5?

• Use minitab refer to lab 8, power=80%.
• Select correct Power graph from the 3 below: _____________
• The recommend sample size is ____________

a b

c

1. A smog alert is issued when the amount of particulate matter in the air is found to be greater than 7 ppm. Samples collected from 16 stations have a mean of 7.8 ppm and a standard deviation of 2 ppm.

1. (10 pts) Is there enough evidence to issue a smog alert? Use Hypothesis Test Template.
2. (4 pts) Given your conclusion, are you at risk of making a Type I error or a Type II error? Provide your answer in the context of the problem.
3. (4 pts) Report a 95% one-sided confidence interval for the mean particulate matter in the air.
4. (4 pts) Perform a power analysis. Compute the difference for which you have 80% power with a sample size of n = 16 stations. Hint: Use minitab refer to lab 8. Select from below:

ab

c

1. (6 pts) In class we discussed the file-drawer problem". Namely, that many studies were not published because they failed to reject the null hypothesis. These studies were filed away in a desk drawer" and never disseminated among the scientific community.
2. Choose one article on the file-drawer problem" from among the three posted with this homework.
3. Read the article, and provide a TYPED summary of the article.
4. Include the title of the article in your summary, do not need to submit the article.