Contrivance of Core Median as Mode of Farm Work Time

Abstract

Average is often used as a representative value of work time. However, when some time values close to the abnormal value are included, the average value becomes larger or smaller than the original value. In farm work, the production process depends on conditions that are difficult to control artificially due to the influence of the natural environment. As a result, abnormal values are likely to appear in the working time, and the distribution tends to be thick on one side. In agriculture, there are several cases where it is desirable to grasp the working time, which is a typical value that can be called the original time value. Therefore, in this study, we selected a kind of mode value as a representative value of farm work time. There are many problems with the existing mode calculation methods. Usually, the mode value is obtained as a class value of the maximum frequency class after making a histogram. However, the mode value thus obtained becomes indefinite depending on how the “anchor position” is determined, even if the class width is fixed; therefore, uniqueness is not guaranteed, making it undesirable. The mean shift method and the approximate L0 norm estimation method are methods that do not use a histogram, although they also have problems. Therefore, we devised a new representative value that is a kind of mode value called the core median. The core median can be calculated using the calculation procedure at spreadsheet software worksheet in this study. In addition, we applied the method on actual farming data for its validation, and we discuss the conditions that should be taken into account while using the method.