Browse > Article
http://dx.doi.org/10.5351/KJAS.2014.27.2.227

DD-Plot for ANCOVA Models  

Jang, Dae-Heung (Department of Statistics, Pukyong National University)
Publication Information
The Korean Journal of Applied Statistics / v.27, no.2, 2014 , pp. 227-237 More about this Journal
Abstract
We use the regression model with the indicator variables in the case that we use qualitative variables as some predictor variables in regression analysis. We use the ANCOVA(Analysis of Covariance) model when comparing the response variable among groups while statistically controlling for variation in the response variable caused by a variation in the covariate. DD-plot can be used as a graphical exploratory data analysis tool before the confirmatory data analysis. With the DD-plot, we can discriminate the difference of groups in the regression model with the indicator variables or the ANCOVA model at a glance. Making DD-plot does not demand the statistical model assumption about error terms in regression model. Several examples show the usefulness of DD-plots as a graphical exploratory data analysis tool for the regression analysis.
Keywords
Data depth; DD-plot; ANCOVA;
Citations & Related Records
연도 인용수 순위
  • Reference
1 Li, J., Cuesta-Albertos, J. A. and Liu, R. (2012). DD-Classifier: Nonparametric classification procedure based on DD-plot, Journal of the American Statistical Association, 107, 737-753.   DOI
2 Liu, R., Parelius, J. M. and Singh, K. (1999). Multivariate analysis by data depth: Descriptive statistics, graphics and inference, The Annals of Statistics, 27, 783-858.
3 Liu, R. and Singh, K. (1993). A quality index based on data depth and multivariate rank tests, Journal of the American Statistical Association, 88, 252-260.
4 http://statmaster.sdu.dk/maskel/docs/sample/ST111/data
5 Jorgensen, B. (1993). The Theory of Linear Models, Chapman & Hall, New York.
6 Kang, G. S. and Kim, C. R. (2013). Linear Regression Analysis, Kyowoosa, Seoul.
7 Kang, M. O., Kim, Y. I., Ahn, C. H. and Lee, Y. G. (1996). Regression Analysis, Yoolgok Pub, Seoul.