IRS13 Word-Word Associations in Document Retrieval Systems chapter M. E. Lesk Harvard University Gerard Salton Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government. IX-25 Occurrences Word Significant? No. of Docs. 1 2 3 4 5 6 7 8 Occ./doc. airfoil yes 8 3 3 2 1.9 affect no 13 11 2 1.2 converge yes 8 4 2 1 1 1.9 correct no 14 13 1 1.0 km yes 7 5 1 1. 2.1 magnitude no 14 13 1 1.0 plan yes 10 7 2 1 1.5 practical no 12 10 1 1 1.25 previous no 14 13 1 1.0 vortex yes 7 4 1 1 1 2.1 Distribution of Occurrences of Significant and Non-significant Words Table 8