How to randomly select 6 sets of trials and randomize them afterwards. (case 27392)

[Researcher321]

For your file named Exp 2.cv, insert a row after trial 48 in the block (e.g., right after row 50). Use a value of 0 in the wgr cell of this new row. This will make DirectRT present only 48 trials randomly selected from the ones in your .csv input file with the same number in the wgr cells.

To ensure that only 48 trials are presented, use the skip feature of DirectRT in this same row (see http://www.empirisoft.com/directrt/h...t_skipping.htm). Skip to the trial that follows the last of the possible 256 trials (i.e., row 259 of the Exp 2.csv file). I would also recommend using unique numbers in the trial cell of all the rows of your .csv input file to avoid possible confusion.

Thank you so much for your response. This solves one huge piece of the puzzle. However, I am still unsure how to randomly select 6 groups out of the 32. Using the attached excel sheet as a reference, I was hoping to find a way to randomly select 6 sets, as grouped in column "I".

Correct me if I'm wrong, but I don't think I can assign these groups their own "rbg" values and then follow your suggested method to solve this.