Reference no: EM132693545

PRACTICE PROBLEMS

Question 1: A clinical trial evaluates a new compound designed to improve wound healing in trauma patients. The new compound is compared against a placebo. After treatment for 5 days with the new compound or placebo, the extent of wound healing is mea¬sured and the data are shown in Table 7-51. Is there a difference in the extent of wound healing by treatment? Run the appropriate test at a 5% level of significance. (Hint: Arc treatment and the percent of wound healing independent?)

Question 2: Use the data in Problem 1 and pool the data across the treatments into one sample of size n = 250. Use the pooled data to test whether the distribution of the percent of wound healing is approximately normal. Specifically, use the following distribution: 30%, 40%, 20%, and 10%, and α = 0.05 to run the appropriate test.

Question 3: Table 7-52 displays summary statistics on the participants involved in the study described in Problem 1. Are any of the characteristics significantly differ¬ent between groups? Justify briefly. (Hint: No calculations, just an interpretation.)

Question 4: An experiment is designed to investigate the impact of different positions of the mother during ultra-sound on fetal heart rate. Fetal heart rate is mea-sured by ultrasound in beats per minute. The study includes 20 women who are assigned to one posi-tion and have the fetal heart rate measured in that position. Each woman is between 28 and 32 weeks gestation. The data are shown in Table 7-53. Is there a significant difference in mean fetal heart rates by position? Run the test at a 5% level of significance.

Question 5: Suppose in the trial described in Problem 8 that patients were recruited from three different clini-cal sites. Use the data in Table 7-56 to test if there is a difference in the proportions of hypertensive patients across clinical sites. Run the test at a 5% level of significance.

Question 6: Recent recommendations suggest 60 minutes of physical activity per day. A sample of 50 adults in a study of cardiovascular risk factors report exercis¬ing a mean of 38 minutes per day with a standard deviation of 19 minutes. Based on the sample data, is the physical activity significantly less than recom¬mended? Run the appropriate test at a 5% level of significance.

Question 7: Suppose a hypertension trial is mounted and 18 participants arc randomly assigned to one of three comparison treatments. Each participant takes the assigned medication and his or her systolic blood.

Attachment:- biostatistics.rar