Reliability Assignment
Instructions: You may use your book to find the appropriate formula. To receive full credit, you must write out the formula and show all of your work. Please make sure you put your name on the paper. Each question is worth 10 points for a total of 50 points.
1. Calculate Cronbach's alpha where N=500 and p=0.25. Provide your recommendation based on the alpha level obtained.
2. Calculate Cronbach's alpha where N=75 and p=0.05. Provide your recommendation based on the alpha level obtained.
3. Calculate Cohen's kappa for Interobserver reliability where Pr(a)=35 and Pr (e)=25. Provide your recommendation based on the kappa level obtained.
4. Calculate Cohen's kappa for Interobserver reliability where Pr(a)=68 and Pr (e)= 60. Provide your recommendation based on the kappa level obtained.
5. Calculate the percent agreement where the # of agreements =350 and the # of disagreements =82. Provide your recommendation based on the percent agreement obtained.
- Formula
α= Np / [1+ p(N-1)]
- Components of the formula
α = Cronbach's alpha
N= number of items
P= mean inter-item correlations
- Interpretation
Range from 0 to 1
Higher the value, the stronger the internal consistency
Acceptable minimum 0.70