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st: choosing how to collapse very large datasets
From
Hind Sbihi <[email protected]>
To
[email protected]
Subject
st: choosing how to collapse very large datasets
Date
Thu, 21 Oct 2010 20:14:24 -0700 (PDT)
Hello stata users
The data I have collected has physiological measurements (variables in col 3 to 7) collected at 256Hz while study participants listen to a song and give the song a rating (last column).
Because of the chosen frequency we generated 256 observations per second.
Every study participant (n=50) listens to 45 second excerpt for each of 37 songs.
The volume of the data set is simply overwhelming at this stage and I am considering different options for starting at least to visualize the data (e.g. rating vs. physiologic responses) before doing any analysis.
My question is: how can I aggregate the data?
Collapse() seems to be the appropriate command but I am wondering which arguments should go in the command.
Below is a snapshot of what the data looks like for the first song for one participant.
time songid hr hraccel scr dscr emg resprate skintemp rating
0 1 000063.73 -00000.87 000001.72 -00000.00 000003.49 000050.44 000028.15 4
.0039063 1 000063.73 -00000.87 000001.72 -00000.00 000003.49 000050.44 000028.15 4
.0078125 1 000063.73 -00000.87 000001.72 -00000.00 000003.49 000050.44 000028.15 4
.011719 1 000063.73 -00000.87 000001.72 -00000.00 000003.49 000050.44 000028.15 4
.015625 1 000063.73 -00000.87 000001.72 -00000.00 000003.49 000050.44 000028.15 4
.019531 1 000063.73 -00000.87 000001.72 -00000.00 000003.49 000050.44 000028.15 4
.023438 1 000063.73 -00000.87 000001.72 -00000.00 000003.49 000050.44 000028.15 4
.027344 1 000063.73 -00000.87 000001.72 -00000.00 000003.48 000050.44 000028.15 4
.03125 1 000063.73 -00000.87 000001.72 -00000.00 000003.48 000050.44 000028.15 4
.035156 1 000063.73 -00000.87 000001.72 -00000.00 000003.48 000050.43 000028.15 4
Many thanks in advance for your suggestions.
Hind
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