Mercurial > hg > aim92
diff man/man1/stats.1 @ 0:5242703e91d3 tip
Initial checkin for AIM92 aimR8.2 (last updated May 1997).
author | tomwalters |
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date | Fri, 20 May 2011 15:19:45 +0100 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/man/man1/stats.1 Fri May 20 15:19:45 2011 +0100 @@ -0,0 +1,132 @@ +.TH STATS 1 "1 September 1993" + +.SH NAME +stats \- calculate some statistics. + +.SH SYNTAX +stats [options] [file] + +.SH DESCRIPTION +Calculate statistics for given frames of each input file and write the +results on the stdout. +If no filenames are given, one input file is expected on the stdin. +Otherwise each given filename is processed in turn. + +.SH OPTIONS + +1. frame, width, samplerate + +The `frame' option selects a sequence of contiguous frames for processing by: + +.nf + frame=a[-b] +.fi + +where `a' and `b' are frame numbers: 1,2,3,...,max The upper limit `b' is +optional, and when it is missing then the frame sequence is a single +frame, otherwise `a' and `b' are inclusive limits. The strings "min" +and "max" are recognised as extreme limits. +Each frame has size `width' samples which +may be given with time units (s or ms), in which case the they +are converted to a number of samples using the given `samplerate' option. +The special option value "width=max" is interpreted as a single frame covering +the whole file. + +2. type + +Datatype for both input and output. Binary types are char, short, int, float, double. +Ascii input (one number per line) is recognised with "type=ascii". + +3. stat + +The statistics available to the `stat' option are: + +.nf + n sample (ie. data set) size + sum area + ss sum of squares + mean sum/n + rms root mean square: square root of ss/n + variance computed with n-1 degrees of freedom + stddev standard deviation: square root of variance + min minimum value + max maximum value + absmax maximum absolute value, ie. max( |max|, |min| ) + range max-min +.fi + + +The variance is the average squared deviation from the mean value, where the +average is computed by dividing by n-1 for a data set of n samples. +The stddev is the square root of this variance. +The stddev would be equal to the rms value for a data set with zero mean, +except that the average squared value is computed using ss/n, while the +average squared deviation from a zero mean value is computed using ss/(n-1). + +Statistics may be given in a comma separated list, for example: + +.nf + stats stat=mean,variance,min,max +.fi + +For each frame of each input file this will output the four statistics in the +data type selected by the `type' option. + +4. line + +When line=on (or -l) output is forced to be ascii irrespective of the `type' option, +and for each file argument in turn stats prints the statistics requested, +in the order they were requested, on one line. +This makes a table (one line per file), and also helps subsequent operations +between statistics. For example, the standard error of the mean (the stddev +divided by the square root of the sample size) can be computed: + +.nf + stats -l stat=stddev,n | awk '{ print $1 / sqrt($2) }' +.fi + +Tables can be formatted using field-width and precision arguments which are +included as silent options. For example, to format columns with a precision +of 4 decimal places with each number right-justified in a field-width of +12 characters: + +.nf + stats -l fieldwidth=12 precision=4 +.fi + +The columns may be left-justified by making the fieldwidth parameter negative. +Output is truncated to integers by setting the precision parameter 0. +For example, to print the sample size of each file as an integer without +setting in a field: + +.nf + stats -l fieldwidth=0 precision=0 stat=n [files] +.fi + +.SH "SEE ALSO" +.LP +options +.SH COPYRIGHT +.LP +Copyright (c) Applied Psychology Unit, Medical Research Council, 1995 +.LP +Permission to use, copy, modify, and distribute this software without fee +is hereby granted for research purposes, provided that this copyright +notice appears in all copies and in all supporting documentation, and that +the software is not redistributed for any fee (except for a nominal +shipping charge). Anyone wanting to incorporate all or part of this +software in a commercial product must obtain a license from the Medical +Research Council. +.LP +The MRC makes no representations about the suitability of this +software for any purpose. It is provided "as is" without express or +implied warranty. +.LP +THE MRC DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING +ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL +THE A.P.U. BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES +OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, +WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, +ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS +SOFTWARE. +