HOW MANY OBSERVATIONS ARE NEEDED FOR REGIONAL ESTIMATION OF SOIL PROPERTIES
HOW MANY OBSERVATIONS ARE NEEDED FOR REGIONAL ESTIMATION OF SOIL PROPERTIES
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DOI：
10.1097/00010694-198303000-00007
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发表时间：
1983-01-01
期刊：
影响因子：
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通讯作者：
WEBSTER, R
中科院分区：
文献类型：
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作者：
MCBRATNEY, AB;WEBSTER, R
区域土壤研究的一个共同任务是确定样本中特定土壤特性的平均值。为此目的所需的观测数量的估计通常是基于经典的抽样理论，而不考虑数据的空间依赖性。因此，这些数字被过分夸大，往往使调查人员不敢追求其目标。本文提出了一种考虑空间相关性的样本量确定方法，即观测值个数的确定方法。该方法依赖于了解感兴趣特性的半变异函数，该函数用于计算每个观测点邻域的方差。然后将方差合并以形成全局方差，从中可以计算标准误差
A common task in regional studies of soil is to determine the mean values of particular soil properties from samples. Estimates of the number of observations needed for this purpose have usually been based on classical sampling theory without regard to spatial dependence in the data. As a result they have been unduly exaggerated and have often daunted investigators from pursuing their aims. This paper demonstrates a method for determining sample size, that is, the number of observations, taking account of spatial dependence. The method depends on knowing the semivariogram for the property of interest, which is used to calculate the variances in the neighborhood of each observation point. The variances are then pooled to form the global variance from which the standard error can be calculated