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<DIV>one way to do this, without any scripting, would be to have several lists.</DIV>
<DIV>1st list: one item - not an X</DIV>
<DIV>2nd list: 7 items, including your X, selected randomly</DIV>
<DIV>3rd list: 1 item - not an X</DIV>
<DIV> </DIV>
<DIV>each of the 3 lists would have the same nested list, call it FontsList, with 4 items in it (32, 72, and two other font sizes). these 4 font sizes would be in a column called FontSize, and items from FontsList would be randomly selected.</DIV>
<DIV> </DIV>
<DIV>then, within your procedure, the TextDisplay item presenting your stimuli would reference the column [FontSize] such that each presented stimulus would pull a fontsize at random from your FontsList.</DIV>
<DIV> </DIV>
<DIV>make sense?</DIV>
<DIV> </DIV>
<DIV>SessionProc</DIV>
<DIV> List1 (1 item, not an X, with FontsList nested)</DIV>
<DIV> PresentationProc</DIV>
<DIV> List2 (7 items, including X, with FontsList nested)</DIV>
<DIV>
<DIV> PresentationProc</DIV>
<DIV> List3 (1 item, not an X, with FontsList nested)</DIV>
<DIV>
<DIV> PresentationProc</DIV></DIV></DIV>
<DIV> </DIV>
<DIV>ben robinson<BR><BR>>>> "Mark Chan" <mr.mark.chan@gmail.com> 10/6/2006 12:56 AM >>><BR></DIV>
<DIV style="COLOR: #000000">'m trying to design a study with Pseudo-Random presentation of stimuli.<BR><BR>Basically this is what i'm looking at:<BR><BR>
<UL>
<LI>I'll be presenting 9 different objects in 25 blocks<BR>
<LI>There is a target object, which we will call "X".
<LI>I need "X" to appear once within each block<BR>
<LI>"X" cannot re-appear back to back.<BR> i.e. <SPAN style="FONT-STYLE: italic">end of block 1</SPAN>, we have... stimuli, stimuli, TARGET, <SPAN style="FONT-STYLE: italic">start of block 2</SPAN> TARGET, stimuli, stimuli...this cannot occur
<LI>It would be preferable if there were at least 3 stimuli between TARGET presentation.
<LI>We do not wish to have repeats of stimuli and target within each block. <BR></LI></UL>Also, i was wondering if you could have the font sizes change randomly (4 different sizes) between stimuli. Say first stimuli, font = 32, next stimui = 72, etc.<BR><BR>Any ideas?<BR><BR>Thanks! </DIV></BODY></HTML>