DOI: 10.22620/SCIWORKS.2016.56.010
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The purpose of the following research is to describe the character, intensity and the tendency of the dynamic alterations in the yields of cereal crops – wheat, maize and barley in Bulgaria, as well as testing the assumption for the existence of a tendency in the development.
The results of the time series analysis are based on the evaluation of the speed of the development, with the help of describing and summarizing indicators of visual presentation of the alterations, based on the graphic method, and the hypothesis testing of a trend existence. The conclusions of the research give indication that due to the large changes in the yield levels, as a result of random or cyclic causes, to reveal a secular trend of development, it is necessary to evaluate time series with sufficient continuance levels.
The tendency in the time series is determined by applying the Box-Ljung Statistics.