Overview
1. First of all process all
your data files as if you were interested in overall mean values, (edit artifacts, extract event traces over the entire
file). If you have only a small amount of relevant data segments and
have marked segments of interest with a dedicated marker channel, you
can reduce the work by loading this marker channel as 'optional
channel' and editing only segments that you jump to by using the 'find
peak'-function from the navigation section.
2. Create timing files for every data file as described above (see
marker
for a
detailed description). This can be automatized using the batchmode of
ANSLAB, activating the 'marker'-option in the dynamic 'batch'-module of
ANSLAB menu window. Later in the process ANSLAB will take every segment
listed in the timing files and extract a given number of seconds before
and after the start of the
segment. The ending time is ignored in this case, to avoid signal
length differences due to timing rounding errors in the extracted
trials. Thus, you can select a subset of segments to include in the
extraction, by manually changing the timing file. Moreover, the first
column of the T-variable can be used to determine the naming of the
averaged segments later on.
3. Extract trials. Takes a defined segment around markers, discards date in between trials
4. Average conditions
5. Average across participants
6. Either export data for statistical analysis in an external statistics software
package, or run statistical tests in ANSLAB. The main advantage of
built-in statistics in ANSLAB, is that ANSLAB can run a large number of
statistical tests quickly without laborious rearrangement of the data.
Thus ANSLAB can generate a F- and P-curves for each tested effect,
allowing you to easily identify intervals of interest (see the
plotting ANOVA results
page for an example). The built-in tests can be
run on single trial data or on averaged responses, which for some
channels can be a gain in terms of signal quality.