Weighted Average Method for Land Grading Design

Based on the theory of the least squares and the statistical properties of the best statistic with an unbiased estimate and minimum variance, a new method for land grading design is presented. Although it is based on least-squares theory, it does not have the cumbersome and time consuming calculations of the terms of the simultaneous equations that appear in the conventional least-squares method. In rectangular fields, the method is as accurate as the conventional least-squares method. In irregularly shaped fields the results are different but the differences are negligible. Since the developed equations can be solved by using a calculator in statistical mode and a readily available table, the proposed method has the advantage of being amenable to hand calculation.