SKIP TABLES FOR THE ROFFMAN SKIP FORMULA

Solution:  Skip Tables for words ranging between 3 and 8 letters are found  at the bottom of this web page and on pages 215 through 220 in Appendix B to my Ark Code book (there is a slight correction below for words 8 letters long).  For a 4-letter word use Table 1B.  On it find that 28 columns = 9 possible skips forward.  Thus Sr = 9.  Now note that 11 rows = 3 possible skips vertically.  Thus Sc = 3.  Now apply the formula which is Skips = 2(Sr + Sc + 2[Sr][Sc])    2(9 + 3 + 2(9)[3]) = 2(12 + 54) = 2(66) = 132 SKIPS.  Now, let us suppose that the 4-letter term occurred at skip 100.  To get an idea of how likely such a term is to be found at an ELS, search a range of 132 skips, such as from skip 101 to skip 232.  The number of "hits" for this term is then divided by letters in the Control (if this is scrambled Torah the number of letters in the Control is the same as in Torah, i.e., 304,805).  The quotient is the Word Frequency Per Letter. This is multiplied by the number of letters on each matrix to reveal Word Expectancy Per Matrix.  It is inherent in this procedure that the larger the number of letters in the matrix, the larger the number of placements possible for any given key word at any ELS.   After determining Word Frequency Per Plot we  apply the  Poisson Equation to see the probability that they are present at least once. This is necessary to determine a true probability for each word. Just because a word is likely to appear once per plot does not imply it will always be there. Words may average out to many times per plot area without actually being in a given plot of that area. Of course, if the expected frequency is sufficiently high we eventually reach a probability like .9999999 which we simply round off as 1.0.