The application of X -1 2 -ARIMA model in analysis on incidence trend of typhoid / 预防医学

Objective To study the function of X -1 2 -ARIMA model in analysis on incidence trend of typhoid. Methods Secular trend,seasonal periodicity and random fluctuations of the monthly morbidity data in Zhejiang province from 2005 to 201 3 were analyzed by X -1 2 -ARIMA model.Results The seasonal fluctuation showed a narrowing trend year by year during 2005 to 201 3.After September,2007,the incidence of typhoid showed a downward trend.After 2008,the annual peak of incidence changed from August to July.The irregular factor may well represent the outbreak. Conclusion The X -1 2 -ARIMA model showed clear secular trend and seasonal periodicity,and the random fluctuation was of great value.