Module 13 Assignment

Tables and the Chi-Square Test

[Refer to the Module 13 Slides for a practice example]

Is there a relationship between treatment and smoking cessation? A study randomly selects a group of 1,025 smokers who are attempting to quit. One group of 352 is using Chantix, one group of 329 is using Bupropion, and one group of 344 is using a placebo. The success of the treatment is measured on whether or not participants smoked in weeks 9-12 of the treatment (this is a yes or no variable).

Part 1:

a.       Complete the table above by filling in the percentages for each of the three treatments (remember that columns will add to 100%)

b.      Write an interpretation statement comparing across the percentages across the row and a summary statement describing the relationship between treatment and smoking cessation.

Part 2

a.       Set up the null and alternative hypothesis for a Chi-Square test of the relationship between treatment and smoking cessation

b.      Use the observed vs expected counts tables below to calculate the Chi-Square value (use the table and formula below). I have done the first cell for you. (Showing your process) Repeat for the next five and then solve for X².

X² = [(155-107)² / 107] + ________ +________+________+________+________

c.       Finally, use the Chi-Square table (pasted below) to find the critical value when DF= (r-1) * (c-1) and alpha = .05. Compare this to the critical value and determine whether or not we can reject the null hypothesis.