摘要：The study reported here is part of a research project, under the Research and Marketing Act of 1946, entitled Anticipating Year-to-Year Changes in Market Supplies Due to Changes in Yields Per Acre. One of the purposes is to learn whether the available records on crop yields per acre contain variations from year to year, or patterns of variations over periods of years, that might be usable in anticipating changes in per acre yields for a year or more in advance. Louis H. Bean here restates his views on the evidence of trends and patterns in crop yields and weather and as a first step in determining the reality of such trends and patterns, Richard J. Foote reports on the application of selected statistical tests to the fluctuations in corn yields and in a constructed series, concluding with a suggestion, for a more appropriate statistical test.
