The Simfit/Excel interface
Abstract
If your data are in the Microsoft Office spreadsheet Excel you may
wish to analyse them using Simfit, and there are three ways this can be
done. You can copy and paste using the clipboard, you can write out a
table in ASCII comma delimited format to a file, or you can use the Excel
macros (called simfit?.xls) distributed with Simfit. In each case you start
in the same way by collecting together the data columns of interest
into a contiguous, selected (i.e. highlighted) block. Note that this
block can only have missing values or text labels if you intend to use
the Simfit program MAKSIM to create a Simfit file, and then the text
must have no spaces in labels. Excel uses tabs to ensure that text like
Date of Birth can represent a single cell, but Simfit regards spaces and
commas as separators, so you have to use labels like Date-of-Birth or similar.
Method 1: Using the clipboard
Copy the selected table to the clipboard and then either paste
it into the Simfit program when asked for data input, or paste it
into program MAKSIM to create a data file.
Method 2: Creating ASCII files
Copy the selected table to a comma delimited ASCII file, but
before this can be read into Simfit it must be processed by
program MAKSIM in order to create a Simfit data file.
Method 3: Using the Simfit Excel macros
You will have to investigate the macros (simfit?.xls) supplied with Simfit
to find one that works for your puroposes. There are several macros
for the alternative versions of Microsoft Office, and there are
variants with different functions. It is necessay to open a simfit?.xls
macro before selecting a data table for writing to a file.
Then, after selecting an Excel table, you open the appropriate macro
from Excel by selecting the Tools options then the macro required
to create a correctly formatted file (if the table is consistent).
Advice
- Simfit files have a header (title then number of rows and columns) and
a trailer (details about the data) but you never include these in the
table selected. Such details are added automatically when clipboard
data is pasted into Simfit, when a table is processed by MAKSIM, or
when the macros are used.
- To analyse a sample for statistics or to create a pie chart you only
need to select a single column.
- To compare samples or do 1-way analysis of variance you create a file
with a matrix if all columns are the same length. Otherwise you create
a file for each column, then you create a library file (using
program MAKLIB) to reference the column files required.
- To do a Fisher exact or chi-square test, or estimate multiple correlations
or plot a bar chart you select a rectangular matrix. To add error bars
to a bar chart you write out a rectangular matrix of errors to be added,
corresponding to the rectangular matrix of bar heights.
- To do curve fitting or plotting you select the first column (in
increasing order) as the independent variable and the second column
as the dependent variable. Note that the macros can be used to make sure
that column 1 is in increasing order.
- Advanced users may wish to add a final column of weights to curve
fitting data tables, or they may wish to prepare plotting files with
error bars by having the low, middle then upper error bar values
in columns 2, 3 and 4. Note that the macros can be used to check that
selected columns only contain positive values.
- Very advanced users will appreciate that the macros can be used
to create special Simfit files, like the files for fitting functions of
several variables or for plotting advanced pie or bar charts.
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