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chapter 19
CHAPTER 19STATISTIC
EXTRACTION
Concepts
T
he Statistic Extraction tool is designed to operate on Net Station averaged or
segmented files. It outputs a tab-delimited text file of the statistical analysis.
The tool contains panes for waveform, source, and wavelet data. Waveform data refers
to the scalp data (in microvolts) acquired with your Geodesic EEG System. Source data
are the cortex data (in nano-amp meters) derived by using EGI’s GeoSource software.
Wavelet data are joint time-frequency information produced when you run the
Wavelet tool on your data.
For each input file of waveform or source data, the Statistic Extraction tool outputs a
tab-delimited text file containing one or more statistical analyses. For both single or
multiple input files of wavelet data, the Statistic Extraction tool outputs a single tabdelimited
text file.
You typically use the Statistic Extraction tool to help determine whether a particular
component is statistically different between experimental conditions. To do this, you
run the Statistic Extraction tool on a multisubject averaged file and import the output
into a statistical software package (for example, SPSS or JMP) for analysis.
For each analysis, you need to specify the following parameters:
• a time window
• a statistical measure (mean amplitude, adaptive mean, minimum amplitude,
maximum amplitude, or latency)
• how the measure is to be reported for each channel group
• one or more categories
• one or more channel groups
Net Station Waveform Tools Technical Manual S-MAN-200-WFTR-001 • December 21, 2006
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