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tabcmp - Student T and F test for mean and variance comparisons
tabcmp
[parameter=value]
tabcmp compares two columns from two tables.
It uses the Student’s t-test and f-test to assess if their means and variances
are significantly different. It also assesses the two distributions using
a non-parametric Kolmogorov-Smirnov test.
t-test different mean? But variances are expected to be the same
tu-test different mean? But variances are allowed different
tp-test different mean? Paired arrays
f-test different variances? Different arrays allowed
ks2 non-parametric Kolmogorov-Smirnov test
The following parameters are recognized in any order if the
keyword is also given:
- in1=
- First dataset, a simple ascii table. No default.
- in2=
- Second dataset. No default.
- col1=
- Column from 1st dataset (in1=). Default:
1.
- col2=
- Column from 2nd dataset (in2=). Default: 1.
- nmax=
- Max allocated lines
in data if from a pipe. Default: 10000.
Here is an example to compare
two gaussian distributions, fully done through NEMO. First create two simple
tables, random gaussian numbers with mean 0 and dispersion 1 (make sure
they are not identical, or use seed=-1 in tabmath):
% nemoinp 1:20 | tabmath - - "rang(0,1)" all > tab1
% nemoinp 1:20 | tabmath - - "rang(0,1)" all > tab2
% cmp tab1 tab2
% tabcmp tab1 tab2
F-test: f=1.33497 prob=0.535006
T-test: t=-0.77149 prob=0.445188
TU-test: tu=-0.77149 prob=0.445285
TP-test: tp=-0.796496 prob=0.435584
KS2-test: ks2=0.15 prob=0.965485
Paired t-Test cannot handle identical arrays.
tabhist(1NEMO)
,
tabplot(1NEMO)
, table(5NEMO)
, nemoinp(1NEMO)
, tabmath(1NEMO)
http://www.physics.csbsju.edu/stats/KS-test.n.plot_form.html
Filessrc/kernel/tab/tabcmp.c AuthorPeter Teuben Update History
7-Oct-97 V0.1 adopted from Numerical Recipes routines PJT
8-oct-97 V0.2 added col1=,col2= and same-table processing PJT
5-oct-00 V0.3 added KS2 test, also from NR PJT
10-aug-03 fixed kstwo() indexing error PJT
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