Time series analysis of the epidemic situation of varicella in Nantong City
TAO Chang-yu;ZHANG Shi-jun;CHEN Yu;Office of Integrated Services,Nantong Municipal Center for Disease Control & Prevention;
Objective The purpose of this study was to establish the predictive model by using SARIMA model to analyze monthly data of varicella cases in Nantong city. Methods Eviews software was used to fit SARIMA model for the monthly data of varicella cases in Nantong city. Firstly,the natural logarithm transformation and difference method was used to make the data sequence stationary. Secondly,parameters of model were estimated and tested. Meantime,the optimal model was selected. Finally,the optimal model was used to forecast and analyze. Results The model ARIMA( 1,0,0)( 1,1,0) 12 was established and indicated by was( 1-B12) lnxt( 1-0.579 4B)( 1+0.312 2B12) = t,which had passed the white noise test( P0.05). All values were accurately fitted with MAPE being 8.90%. Accordingly,the model was applied to predict the monthly numbers of varicella cases during the first half of 2015,which were 67,36,64,55,72 and 87 respectively. Conclusion The model is better fitted with the time series of varicella cases in Nantong city. Relevant preparatory prevention measures should be taken against the varicella outbreak according to the forecast results.
【CateGory Index】： R725.1;R181.3