A Study On The Middle-long Period Population Trend Of Hubei Province Based On The Gray Combined Forecast Method

The population issue is essential of the society and economy development, and itis also the base of all society and economy decision-making. It has realisticsignificance to forecast the population trend and change character correctly and makeout correct judge that matches the population change trend accordingly.Since 1949, the population growth of Hubei province has been undergoing fourstages, during which time the total population has increased from more than 25.8million in 1949 to more than 60.16 million in 2004. From 1949 to 2004, we havewitnessed two high birthrate stages, in each the population accrual rate reached1.92%. During the second high birthrate stage, the total population increased by morethan 670 thousand annually, which makes the total population of Hubei pierced into60 million and hence became a big population province of our country.Along with the population policy's adjustment of our country and theimprovement of people's living standard, the expected life-span of people hasbecome longer than ever before and the population growth character has changed a lot,the annual growth rate will level off or even slow down. Under this situation, it isnecessary to drop out the population change trend of Hubei province in the coming10-15 years.In this dissertation, the author takes the way of ration research and adopts thehistorical population data to drop out the trend curve and the model of the populationchange of Hubei province, and the combined forecast have been done by extrapolatingthe change trend.The combined forecasting analysis is a kind of synthetic forecasting method, inwhich all different kinds of forecasting models and methods are assembled and usedto do the information forecasting work. The theory on the combined forecastingmodel and its application is popular at the present time. The key of handling thecombined forecasting model is that the single model should be good and the weight ofthe single model should be endowed correctly.In this dissertation four single models, GM(1,1),4 times multinomial,logarithmand power model, are chosen to forecast the population change trend of Hubeirespectively. On this base, the weight of each single model is endowed by way ofstandard distance. From the analysis, we can see that all four single models can draftthe time-series data well, but the 4 times multinomial does not suit well when it isused for the long- term trend forecasting. On the contrary, the combined forecastmodel shows good statistic outcome in the average relative error,precision and thestandard error of the remnant.From the forecast analysis we draw a conclusion that the population of Hubeiprovince will maintain a low accrual rate for a rather long time in the coming yearsand the total population of Hubei province may reach the level of 61.8585-62.7155,66.4707-67.5273,77.1538-78.5594 million by the year of 2010,2015,2020respectively.