Some Applications of Chi-Square Test
Not what you're looking for?
I need to know which equation to use and detailed steps to answer the following question by hand.
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 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.
Purchase this Solution
Solution Summary
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.
Purchase this Solution
Free BrainMass Quizzes
Terms and Definitions for Statistics
This quiz covers basic terms and definitions of statistics.
Know Your Statistical Concepts
Each question is a choice-summary multiple choice question that presents you with a statistical concept and then 4 numbered statements. You must decide which (if any) of the numbered statements is/are true as they relate to the statistical concept.
Measures of Central Tendency
Tests knowledge of the three main measures of central tendency, including some simple calculation questions.
Measures of Central Tendency
This quiz evaluates the students understanding of the measures of central tendency seen in statistics. This quiz is specifically designed to incorporate the measures of central tendency as they relate to psychological research.