## About proportions in selection pool

 Author Message derodriguezz Respected Member Group: Forum Members Posts: 10, Visits: 51 Hi everyone!I'm trying to set 26 trials in which there should be 16 trials of "choice" and 10 trials of another two kinds ("posneg", "arounon"- 5/5). I'm setting the proportions in the selection pool but I always have an unequal quantity of trials between "posneg" and "arounon" (4/6). This is the code i'm using/trials = [1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37,39,41,43,45,47,49,51 = noreplacenorepeat(choice, choice, arounon, posneg); 2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44,46,48,50,52 = rate]thanks to all of you! Dave Supreme Being Group: Administrators Posts: 9.2K, Visits: 39K +xderodriguezz - Tuesday, March 20, 2018Hi everyone!I'm trying to set 26 trials in which there should be 16 trials of "choice" and 10 trials of another two kinds ("posneg", "arounon"- 5/5). I'm setting the proportions in the selection pool but I always have an unequal quantity of trials between "posneg" and "arounon" (4/6). This is the code i'm using/trials = [1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37,39,41,43,45,47,49,51 = noreplacenorepeat(choice, choice, arounon, posneg); 2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44,46,48,50,52 = rate]thanks to all of you!1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37,39,41,43,45,47,49,51 = noreplacenorepeat(choice, choice, arounon, posneg); you are taking 26 samplesfrom 1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37,39,41,43,45,47,49,51 = noreplacenorepeat(choice, choice, arounon, posneg); four elements26 / 4 = 6.5since there can be no such thing as "half a trial" (.5), you're getting varying result. The math just doesn't work and your selection pool is not set up correctly.You've defined a 2:1:1 ratio with noreplacenorepeat(choice, choice, arounon, posneg), but you actually want a 16:5:5 ratio.2:1:1 and 16:5:5 are mathematically not the same.2:1:1 would be mathematically equivalent to 16:8:8 or 10:5:5, but it is not mathematically equivalent to 16:5:5.In fact, you cannot simplify 16:5:5 further, because there is no common divisor for 16 and 5. In other words, you actually need to set up your pool like this:1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37,39,41,43,45,47,49,51 = noreplace(choice, choice, choice, choice, choice, choice, choice, choice, choice, choice, choice, choice, choice, choice, choice, choice, arounon, arounon, arounon, arounon, arounon, posneg, posneg, posneg, posneg, posneg); Edited 8 Months Ago by Dave