On 4 Aug 2003 06:14:01 -0700, [EMAIL PROTECTED] (Pingu) wrote: > Hello all statistics altruists - > > I have run a between subjects experiment testing subjects' speed of > dialling from a mobile phone under 2 different conditions. 12 subjects > each dialled the same 10 names under both conditions and i want to do > run t-tests in SPSS to see if there is an effect of condition on > dialling time. > > I am pretty sure that i need to be running a 2-tailed "paired samples" > t-test in SPSS to do the analysis i want. The problem is i am not sure > that i have set out my data correctly for this. > > At the moment i have 2 columns representing the 2 conditions. Each > column contains 120 rows of data (12 subjects x 10 dial attempts). I > then choose [column 1 vs column 2] in the "paired samples t test" box > of SPSS. > > Is this correct? I have the feeling that this set out may be treating > the data as if there were 120 participants instead of 12. Im not even > sure if this makes any difference, but i am a novice with very little > available support and i just wanted to make sure.
N=12, for an independent test; and you are correct in being suspicious where it looks like N=120. For the short way (than Thom's): aggregate by Subject, to get one scores for each Subject for each Condition. Then do the paired t-test. You have the data in a form so that you could, if you want, carry out 12 paired t-tests, one for each Subject. That might offer insight about the consistency of the advantage (if there is one). -- Rich Ulrich, [EMAIL PROTECTED] http://www.pitt.edu/~wpilib/index.html "Taxes are the price we pay for civilization." Justice Holmes. . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
