Stratified Sampling Study Of Oncomelania Space Based On Auxiliary Variable And Neyman Allocation

As the unique intermediate host of schistosomiasis,the spatial distribution and diffusion of Oncomelaniahupensis is influenced by various environmental factors.The Oncomelaniahupensis in the marshland-type schistosomiasis epidemic region has characteristics of wide geographic distribution,strong spatial uncertainty and poor distributional unithood.Optimization and simplification of the current survey methods of Oncomelaniahupensis will be helpful to improve the accuracy and speed of Oncomelaniahupensis investigation in the marshland-type schistosomiasis epidemic region and make best use of the limited schistosomiasis control resources.A experimental sample field of 50 m x 50 m was selected in Chayegang marshland,Henghu farm,in the Panyang lake region.The current sampling frame(0.33m×0.33m)of the schistosomiasis control department was taken as the basic sampling unit and continuous full coverage push-broom method was used to investigate the number of Oncomelaniahupensis,plant type,height and cover degree of plants in each sampling frame.STATA14.0 software was adopted and four plant factors(height and cover degree of Carex cinerascens and Triarrhena lutarioriparia miscanthussacchariflorus)that are closely related to breeding of Oncomelaniahupensis were taken as auxiliary variables of spatial layering.K-means clustering method was used to conduct spatial clustering.The Neyman allocation method of stratified sampling was used to determine the sample size of each spatial layering and samples were randomly selected in each layer.The overall mean value,variance and sampling error were estimated.Results:(1)The effect went best when the experimental field was divided into 7 layers.The relative error was 10.11% and the absolute error is 0.06.(2)Auxiliary factors factors on vegetation sampling stratification research variable space snail is feasible,and the vegetation factor in survey data when the observation is simple and convenient.Different sampling methods for snail sampling,stratified sampling found the highest accuracy,breaking the schistosomiasis control part of the snail survey method.(3)The stratified spatial sampling method of Oncomelaniahupensis based on auxiliary variable vegetation attributes has a higher accuracy and the workload is lower in comparison with the current systematic sampling method of the schistosomiasis control department in China.