论文部分内容阅读
分级统计法就是预报量和预报因子分为多级。用数理统计预报昆虫发生期和发生量的一种统计预报方法。这个方法运算简便,易学易懂,且预报准确率较高,值得推行。 一、基本原理 将预报因子x分成k级(k=1,2,3,…,s),预报量y分成l级(l=1,2,3,…,s),然后把历年测报数值,按预报要素(预报因子和预报量通称谓预报要素,简称要素)分级标准演化为分级表,组建x_1;x_2,…x_m的列联表,在列联表的基础上计算概率贡献进行预报。 第j个预报因子对预报量y处于l级的概率贡献公式为:
Grading statistics is forecasting and forecasting factors are divided into multi-level. A Statistical Prediction Method for Forecasting Insect Occurrence and Occurrence with Mathematical Statistics. This method is simple, easy to learn and easy to understand, and the prediction accuracy is high, it is worth implementing. First, the basic principle of the forecast factor x is divided into k-level (k = 1,2,3, ..., s), forecast the amount of y is divided into l (l = 1,2,3, ..., s) , According to the grading standard of forecast elements (forecast factor and forecasting amount, the elements of the title, abbreviation), the classification table evolves into a rating table, and the contingency table for xl, x_2, ... x_m is set up to calculate the probabilistic contribution based on the contingency table. The jth forecasting factor contributes to the probability that forecasting quantity y is at level l: