@misc{Górski_Tadeusz_A_2009, author={Górski, Tadeusz}, volume={82}, number={1}, copyright={Rights Reserved - Free Access}, address={Warszawa}, journal={Geographia Polonica}, howpublished={online}, year={2009}, publisher={IGiPZ PAN}, language={eng}, abstract={An important source of risk in agricultural production is the variability to crop yields reflecting irregularly changing weather. This variability may be described as a stochastic process that has a function of density. Analyses of historical data on crop yields reveal that the function of density changed from right-skewed to left-skewed, along with increasing mean yields. All examined yields of crops cultivated recently in Poland demonstrate the left skew, which does not diminish with the aggregation of acreage. A fairly good approximation of the probability distribution for actual yields may be obtained using the log-normal distribution with an inverted abscissa.}, type={Text}, title={A probability distribution for crop yields in Poland}, URL={http://rcin.org.pl/igipz/Content/55501/PDF/WA51_74830_r2009-t82-no1_G-Polonica-Gorski.pdf}, keywords={crop yields, density function, log-normal distribution, area aggregation, scaling of variance}, }