Random Effects Model For The Analysis Of Data Sewage

Longitudinal data refers to each individual at different times to observe and get the cross-section and by the time series of data together. Longitudinal data of the biggest advantages is that it would cross-section of data and time series data combined with a better analysis of the individual changes in trends over time. However, due to the same individual at different times to repeat the observation, but also between the individual and there are some differences. So when the model should give full consideration to individual differences, in recent years longitudinal data analysis in biology, medicine, psychology and other fields have a broad application of this paper, fixed-effect model, random effects model of a city's sewage data done Analysis and comparison. The article is divided into three parts, the first longitudinal data on a brief introduction to a city sewage collate data. The second part of a fixed effect model, random effects model and gradually take the progressive Contrast the way. Part III use SAS software to analyze discussions.