Blood Plasma Let x be a random variable that represents the pH of arterial plasma. For healthy adults, the m

Question

Blood Plasma Let x be a random variable that represents the pH of arterial plasma. For healthy adults, the mean of the x distribution is U= 7.4 . A new drug for arthritis has been developed. However, it is thought that this drug may change blood pH. A random sample of 31 patients with arthritis took the drug for 3 months. Blood tests showed the average pH to be x = 8.1 with sample standard deviation s = 1.9 Use a 5% level of significance to test the claim that the drug has changed (either way) the mean pH level of the blood.

a) What is the level of significance? State the null and alternate hypotheses.

b) What sampling distribution will you use? Explain the rational for your choice of sampling distribution. What is the value of the sample test statistic?

c) Find (or estimate) the P-value. Sketch the sampling distribution and show the area corresponding to the P-value.

d) Based on your answers in parts(a) to (c), will you reject or fail to reject the null hypothesis? Are the da

Answer 1

Even though this question appears to have a medical context, it is actually a stats problem in disguise.  (In reality, a pH of 8.1 is considered life-threatening metabolic alkalosis.)  http://www.emedicine.com/med/TOPIC1459.H...

Anyway, I suspect this is something a stats prof cooked up.  You will have more luck posting this in Mathematics or Homework Help:

http://answers.yahoo.com/dir/;_ylt=AjMRx...

http://answers.yahoo.com/dir/;_ylt=Ap6YD...

Good luck.