Several Forecasting Methods Of Zhejiang Province's GDP And Their Comparison

Gross Domestic Product(GDP)is the core index of a national economic accounting,and the country can make relevant economic policies based on the situation reflected in GDP so as to make reasonable adjustments to the economic situation.Therefore,it has important significance for nation to regulate and control the economy.Taking Zhejiang province as an example,this paper forecasts GDP by ARIMA model,GM(1,1)model,neural network model and combination model,and then compared the results.The paper is divided into four chapters.The first chapter introduces the research background and current situations of the topic.The second chapter introduces the related theories.The third chapter is the main work of this paper,GDP of Zhejiang province is forecasted by different methods.Firstly,ARIMA model is selected for analysis.The data are from two dimensions: annual and quarterly.The results show that the short-term forecast effect is good,and the quarterly data is relatively better.Secondly,grey prediction is chosen to forecast.We use the grey model optimized by the metabolism algorithm,the average relative error of the GDP forecast in the next three years is only-0.48%.The BP neural network is selected again,and the average error is controlled within 5% by taking advantage of its characteristics of introducing nonlinear mapping.Finally,the paper uses the combination models to make predictions.The fourth chapter is the summary of the analysis results.The grey model optimized by metabolic algorithm in a single model has the best prediction effect,and its prediction of GDP for Zhejiang Province will reach 5596.67 billion yuan,6073.182 billion yuan and 6554.5447 billion yuan in 2018-2020.Among the combination forecast models,the gray model combined with the neural network model has the best prediction effect.Using this model,the prediction values of GDP for Zhejiang province in 2018-2020 will reach 55993.67,60741.55,65835.45 billion yuan.Both models show that economic level of Zhejiang province will be further improved in the future.