Sequential Analysis of Statistical Data: Theory. SRG Report 75 / AMT Report 301, September 1943. Restricted. [With:] Sequential Analysis of Statistical Data: Applications, SRG Report 255, 1945

First edition, very rare, of Wald's seminal invention of 'Sequential analysis', developed while he was in charge of Columbia University's Statistical Research Group (SRG) in response to the demand for more efficient methods of industrial quality control during World War II. It was published four years later in his well-known book of the same title. "The notion that in some sense it is economical to observe and analyze data sequentially, rather than to observe and analyze a single sample of predetermined fixed size, was not a new one. Intuitive support for this notion is immediate; if the evidence shown in sequentially unfolding data is sharply one-sided, it seems reasonable to believe that the inquiry can be terminated early, with lengthier inquiries reserved for those situations in which the issue at hand appears, via the sequentially unfolding data, to be in greater doubt. This notion and the partial mathematical formulation of it were to be found in the statistical literature; among those who dealt with it before Wald was Walter Bartky of Chicago, and among Wald's contemporaries, George Barnard, working in England. But again it was Wald, in 1943, who first formulated mathematically and solved quite generally the problem of sequential tests of statistical hypotheses" (DSB). Some sections of the 'Applications' state 'revised', indicating that they are later issues. Both parts are very rare. No copies are listed on COPAC and none have appeared at auction. Theory: 4to, pp. [iii], iv-ix, [1], 179. Reproduced typescript. Original dark green printed wrappers (spine rubbed with partial loss of lettering, signs of tape removal from spine, corners a bit worn). Applications: Seven sections plus Appendices, 4to, pp. 17, 116, 57, 25, 18, 39, 44, 41, reproduced typescript with coloured printed card titles for each part. Bound in the original ring binder with printed label on front cover and spine.…