----- Forwarded message from
"[email protected]" <[email protected]> -----
Date: Wed, 3 Apr 2013 10:54:30 -0400
From: "[email protected]"
<[email protected]>
Reply-To: "[email protected]"
<[email protected]>
Subject: independent variable files
and regression
To: [email protected]
Hello guys,
I would like to do a "Regression" in tpsRegr and I don´t know how to do that. I´m following the instructions of an online workbook called "A Practical Companion to Geometric Morphometrics for Biologists: Running analyses in freely-available software" by Miriam Leah Zelditch, Donald L. Swiderski, and H. David Sheets.
The following text passage is from that online workbook. Here they tell me how to do a regression in tpsRegr, however, I have no Idea what an "independent variable file" could be and how to construct one.
"Regression in tpsRegr
To
run tpsRegr, you need a shape data file and an independent variable file. The
shape data file can be in either *.tps or *.NTS format, the independent variable
must be in *.NTS format. The first line of the independent variable file thus
contains the control line giving the matrix type (1), number of rows (which is
your sample size), number of columns (the number of variables in the file), and
the missing data option (0). If you labeled the independent variable, add an L
to the third (column) number, e.g. 1L. The remainder of the file consists of the
column(s) of values for your independent variable. For studies of allometry, you
can produce your independent variable file within tpsRegr if you used the scale
factor in tpsDig. Go to the File menu, select Save and then select centroid
size. That produces a file of centroid sizes in *.NTS format. If you want to do
the analysis using log-centroid size instead, open your *.NTS file in a
spreadsheet and add a second column, this one of log-transformed values. Just
remember to change the control line to a 2 for the number of columns and
whenever you have two or more variables in the file, it is useful to include
their labels, so make sure that the control line has 2L for the number of
columns. Below that control line, add a line with the two labels in it, e.g. CS
LCS (no punctuation goes in this line). Save that as a text file with an *.NTS
extension (you may have to change the name of the file if your spreadsheet
automatically adds *.txt to all files that are saved as text files)."
Is there anyone among you who could help me out with this?
Thank you very much,
Bernd
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