Research On Linear Mixed Effect Model Of Water Pollution In Kunming Dianchi Lake

In this paper,based on the water quality changes of Dianchi Lake from 1987 to2015,the Bayesian linear mixed effect model is used to analyze and study the water pollution in Dianchi Lake.According to the posterior probability density function of the parameter,Bayesian estimation is performed on the parameter using NUST sampling.In order to compare the difference between balanced and unbalanced data and select the optimal model,the random intercept model,random slope model and random slope model with covariates of these two types of data under different sample sizes are considered,In the same model and the same sample size,the fitting effect of unbalanced data is worse than that of balanced data,and the prediction effect of the random slope model with covariate is the best of the three models The predicted value of the response variable and the true value basically coincide.In the empirical part,three models are considered for the water pollution data of Dianchi Lake.Among them,it is derived from the random intercept model that the COD of Dianchi Lake will have some fine-tuning with the change of year;it is derived from the random slope model that the COD of the chemical oxygen demand changes little over the course of a year;According to the random slope model with covariates,the correlation of water pollution in Dianchi Lake is predicted and the pollution situation in Dianchi Lake is predicted.Finally,according to the actual situation of Dianchi Lake,some targeted suggestions are provided for its governance.