I need to know which equation to use and detailed steps to answer the following question by hand.

The following datawere 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 χ2> ________

Z =

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 χ2.

χ2= ________

Based on comparing the computed χ2 to the rejection level χ2 which of the following is (are) true?

A. We have statistically significant evidence at alpha=0.05 to show that H0 is false.

B. Treatment and percent wound healing are not independent.

C. Treatment and percent wound healing are independent.

D. a and b.

The solution gives detailed steps on performing a chi-square test for checking independence for multiple groups. Also, another chi-square test using expected frequency technique is shown and explained.