How to do an excel spreadsheet for the problem below:

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 measured and the data are shown here.

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?)

Answer:

Step 1. Set up hypotheses and determine level of significance.

H₀: Treatment and percent wound healing are independent.

H₁: H₀ is false. = 0.05

Step 2.Select the appropriate test statistic.

The condition for appropriate use of the above test statistic is that each expected frequency is at least 5. In Step 4 we will compute the expected frequencies, and we will ensure that the condition is met.

Step 3.Set up decision rule.

df = (2 - 1)(4 - 1) = 3 and the decision rule is: Reject H₀ if c² 7.81

Step 4.Compute the test statistic.

We now compute the expected frequencies using the formula:

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

The top number in each cell of the table is the observed frequency, and the bottom number is the expected frequency (shown in parentheses).