Collected in a clinical trial evaluating
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 (n=125) | 15 | 37 | 32 | 41 |
| Placebo (n=125) | 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?
