On Testing Varieties of Cereals

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Biometrika Trust is collaborating with JSTOR to digitize, preserve and extend access to Biometrika. THE object of testing varieties of cereals is to find out which will pay the farmer best. This may depend on quality, but in general it is an increase of yield which is profitable, and since yield is very variable from year to year and from farm to farm it is a difficult matter upon which to obtain conclusive evidence.Yet it is certain that very considerable improvements in yield have been made as the result of replacing the native cereals by imnproved varieties; as an example of this I may cite the case of Ireland, where varieties of barley have been introduced which were shown by experiment to have an average yield of 150/0 to 200/0 above those which they replaced. This represents, probably, a gain to the country of not less than Y?,250,000 per year. As. the cost of experiments from the commencement to the present time cannot have reached ?40,000 the money has been well spent. ORIGIN OF VARIETIES.In the first place the ordinary cereals, wheat, barley, oats, and so on (maize is not here considered), are all self-fertilized and occur in races broadly distinguished by different botanical characters-Potato Oats, Rivett Wheat, Chevalier Barley, and so forth.Besides these botanically distinguishable races, it is possible to pick out strains from commercial seed which differ from one another in all kinds of ways: time of ripening, percentage of nitrogen, yield, etc., although botanically the same. Many of these strains have been selected from time to time, certainly from the end of the eighteenth century up to the present time.Finally there are hybrids, the result of deliberate crossing, and the selection of the best individuals out of the many thousands which may be grown in three generations is one of the more difficult problems with which the plant breeder has to deal, but it is only after he has made his preliminary selection that his hybrids concern the experimenter who is testing varieties. Owing to the fact of self-fertilization, the various races, strains, and even to a large extent the hybrids, remain practically constant from year to year if once pure seed has been obtained. 18-2This content downloaded from 91.229.248.154 on Wed, 18 Jun 2014 14:50:52 PM All use subject to JSTOR Terms and Conditions 272 On Testing Varieties of Cereals CHIEF SOURCES OF ERROR.The peculiar difficulties of the problem lie in the fact that the soil in which the experiments are to be carried out is nowhere really uniform; however little it may vary to the eye, it is found to vary not only from acre to acre but from yard to yard, and even from inch to inch. This variation is anything but random, so th...

Rationale for and Methods of Superiority, Noninferiority, or Equivalence Designs in Orthopaedic, Controlled Trials

“…Superiority trial design and analysis, as we most commonly encounter it today, started in the early 1900s, when William S. Gosset encountered the problem of having to find the best barley to brew Guinness beer [50,51]. He developed a mathematical method, the t-test, to compare small samples and published it using his pen name ''Student'' because of Guinness' nondisclosure policy, thus the ''Student's t-test'' [50,51].…”

“…He developed a mathematical method, the t-test, to compare small samples and published it using his pen name ''Student'' because of Guinness' nondisclosure policy, thus the ''Student's t-test'' [50,51]. This work laid the cornerstone for two related indices pertaining to superiority (and to noninferiority and equivalence): p values and confidence intervals [59].…”

W.S. Gosset and Some Neglected Concepts in Experimental Statistics: Guinnessometrics II

“…Student wrote to his collaborator and friend, Egon S. Pearson -son of Karl, co-author with Neyman, editor of Biometrika, and chair of the Statistics Department at University College London -using no uncertain terms: 51 Obviously the important thing [Student said Student (1911). 49 Student (1911Student ( , 1923. 50 See Ziliak (2011a) for discussion of Student and post-Student experimental philosophy not considered by field experimentalists such as List (2009), Duflo et al (2006), Banerjee and Duflo (2011), and Karlan and List (2007), all of whom claim to take their cues from Fisher.…”

“…57 Rothman et al (2008); Bruhn and Mackenzie (2009);Heckman and Vytlacil (2007);Ziliak (2010). 58 Student (1923); Gosset (1936);. and permutation of the experiment, given the chosen nrk design and the number of experiments (farms) in the series.…”

“…Fisherrandomization and significance, measured by the p-value, does not. Said Jeffreys again, citing Student (1923Student ( , 1938 as the source of his ideas: 84 There will in general be varietal differences; we have to decide whether they are large enough to interest a farmer, who would not go to the expense of changing his methods unless there was a fairly substantial gain in prospect. There is, therefore, a minimum difference that is worth asserting.…”