2. The following data were collected in a clinical trial evaluating 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 measured and the data are shown below.

	Percent Wound Healing
Treatment	0-25%	26-50%	51-75%	76-100%
New Compound ()	15	37	32	41
Placebo ()	36	45	34	10

Is there a difference in the extent of wound healing by treatment? (Hint: Are treatment and the percent wound healing independent?) Run the appropriate test at a 5% level of significance.

df= ________

alpha= ________

Reject H₀ if ²_>________

Compute expected frequencies

Expected Frequency = (Row Total * Column Total)/N.

Complete the expected frequencies for each cell.

	Percent Wound Healing	Total
Treatment	0-25%	26-50%	51-75%	76-100%
New Compound	15 ( )	37 ( )	32 ( )	41 ( )	125
Placebo	36 ( )	45 ( )	34 ( )	10 ( )	125
Total	51	82	66	51	250

Compute ².

²₌ ________

Based on comparing the computed ² to the rejection level ² which of the following is (are) true?

• We have statistically significant evidence at .05 to show that H₀ is false.
• Treatment and percent wound healing are not independent.
• Treatment and percent wound healing are independent.
• a and b.

3. A clinical trial is conducted comparing a new pain reliever for arthritis to a placebo. Participants are randomly assigned to receive the new treatment or a placebo and the outcome is pain relief within 30 minutes. The data are shown below.

	Pain Relief	No Pain Relief
New Medication	44	76
Placebo	21	99

Is there a significant difference in the proportions of patients reporting pain relief? Run the test at a 5% level of significance.

Reject H₀ if Z < ________ or if Z > ________

alpha= ________

⁼ ________

⁼ ________

= ________

Z = ________

Based on comparing the computed z to the rejection level z which of the following is (are) true?

• We have statistically significant evidence at .05 to show that H₀ is false.
• We have statistically significant evidence at .05 to show that there a significant difference in the proportions of patients reporting pain relief.
• We do not have statistically significant evidence at .05 to show there a significant difference in the proportions of patients reporting pain relief.
• a and b