NAME
welch_t_test_one_sided - One-sided Welch's t-test
SYNOPSIS
#include "stat/stat_test.h"
Example compile flags (system dependent):
-DLINUX_X86_64 -DLINUX_X86_64_OPTERON -DGNU_COMPILER
-I/home/kobus/include
-L/home/kobus/misc/load/linux_x86_64_opteron -L/usr/lib/x86_64-linux-gnu
-lKJB -lfftw3 -lgsl -lgslcblas -ljpeg -lSVM -lstdc++ -lpthread -lSLATEC -lg2c -lacml -lacml_mv -lblas -lg2c -lncursesw
int welch_t_test_one_sided
(
double m1,
double m2,
double v1,
double v2,
int n1,
int n2,
double *t_prime_ptr,
int *df_ptr,
double *effect_size_ptr,
double *p_value_ptr
);
DESCRIPTION
This routine performs a one-sided Welch's t-test. It is safe to use this when
a regular t-test is wanted. The Welch's version is slightly better when the
statistics of sizes of the two groups are quite different.
This routine provides the t-statistic, the degrees of freedom, the effect
size, and the p-value. The p-value is the integral of the lower or upper
tail, depending on whether the t-statistic is negative or positive.
Computing the p-value is currently handled by calling a GSL routine. If it is
not available, then ERROR is returned, but the values for the t-statistic and
the degrees of freedom should be fine. However, if only those two values are
needed, then better to use the routine welch_t_statistic();
Any of the four pointers composing the last four parameters can be NULL.
This is interpreted as the calling program not being interested in the
result.
DISCLAIMER
This software is not adequatedly tested. It is recomended that
results are checked independantly where appropriate.
AUTHOR
Kobus Barnard
DOCUMENTER
Kobus Barnard
SEE ALSO
welch_t_statistic