Date: Mon, 15 May 2006 09:09:50 +1000 Simon Freidin "SPSSX(r) Discussion" Simon Freidin Re: counting valid reactions in a given time To: Philippe Rast <000501c6779f\$14e894d0\$6500a8c0@tower> text/plain; charset=US-ASCII; delsp=yes; format=flowed

compute numclick=0. compute rttot=0.

do repeat x=rt2 to rt10/y=1 to 9. if rttot<=25 rttot=sum(rt1 to x). if numclick=0 and rttot>25 numclick=y. end repeat. if numclick=0 numclick=nvalid(rt1 to rt10). exe.

On 15/05/2006, at 7:40 AM, Philippe Rast wrote:

> Dear List > > We did a reaction-time experiment which ought to last 25 sec. > People had > to point on a certain dot and press the mouse button - for every > correct > answer the reaction was recorded. The idea was to count the clicks per > 25 seconds. > Now, something went wrong and the program sometimes did not stop after > 25 seconds. So lots of subjects hade more time for the task and hence > more clicks. > > Since I have the reaction times I could check, how many clicks were > performed in the first 25 seconds. But how can I do this? > > e.g.: > > data list free/rt1 to rt10. > begin data > 2, 3, 1, 2, 3, 2, 1, 4, 2, 3 > 5, 6, 4, 3, 5, , , , , > 4, 5, 7, 6, 5, 6, 4, 6, 7, 5, > end data. > > comp sum=sum(rt1 TO rt10). > variable label sum 'reaction times summed'. > comp clicks=nvalid(rt1 TO rt10). > exe. > > Case one has reacted 10 times in 25 seconds, while case two has > reacted > 5 times in 25 seconds. > Now, case 3, has reacted 4 times in 25 seconds but the program did not > stop and the person was allowed to click for 55 seconds. Now doing a > NVALID gives me 10 - but in 55 seconds. > I would like SPSS to start adding the rt's up to 25 seconds and then > give me the number of variables added, so that case three would be 4. > > Has anyone an idea how to do this - in reality the rt's are > measured in > milliseconds and some of the 600 subjects clicked up to 550 times. The > solution aught to be applicable in syntax :-) ? > > Thanks in advance! > Philippe

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