#include "pool.h"
#include "hash.h"
#include "stats.h"
+#include "t-test.h"
/* (specification)
"T-TEST" (tts_):
static struct cmd_t_test cmd;
+int value_compare(const union value *a, const union value *b, int width);
static struct pool *t_test_pool ;
static int n_groups_values;
static union value groups_values[2];
+/* Array of statistics for each group */
+typedef struct t_test_proc group_stats_t[2];
+static group_stats_t *groups_stats;
+
+
+
+
/* PAIRS: Number of pairs to be compared ; each pair. */
static int n_pairs = 0 ;
struct pair
/* A function to create, populate and submit the Paired Samples Correlation
box */
-void pscbox(struct cmd_t_test *cmd);
+void pscbox(void);
/* Structures and Functions for the Test Results Box */
static void paired_precalc (void);
static void paired_postcalc (void);
-static int compare_var_name (const void *a_, const void *b_, void *v_ unused);
-static unsigned hash_var_name (const void *a_, void *v_ unused);
+static void group_precalc (void);
+static int group_calc (struct ccase *);
+static void group_postcalc (void);
+
+
+static int compare_var_name (const void *a_, const void *b_, void *v_ UNUSED);
+static unsigned hash_var_name (const void *a_, void *v_ UNUSED);
+
int
case T_PAIRED:
procedure(paired_precalc,paired_calc,paired_postcalc);
break;
+ case T_IND_SAMPLES:
+ procedure(group_precalc,group_calc,group_postcalc);
+ break;
+
}
if ( mode == T_PAIRED)
{
- pscbox(&cmd);
+ pscbox();
}
trbox_create(&test_results_box,&cmd,mode);
}
static int
-tts_custom_groups (struct cmd_t_test *cmd unused)
+tts_custom_groups (struct cmd_t_test *cmd UNUSED)
{
lex_match('=');
static int
-tts_custom_pairs (struct cmd_t_test *cmd unused)
+tts_custom_pairs (struct cmd_t_test *cmd UNUSED)
{
struct variable **vars;
int n_vars;
for (i=0; i < cmd->n_variables; ++i)
{
+ int g;
+
tab_text (ssb->t, 0, i*2+1, TAB_LEFT, cmd->v_variables[i]->name);
if (val_lab1)
else
tab_float(ssb->t, 1 ,i*2+1, TAB_LEFT, groups_values[0].f, 2,0);
+
if (val_lab2)
tab_text (ssb->t, 1, i*2+1+1, TAB_LEFT, val_lab2);
else
tab_float(ssb->t, 1 ,i*2+1+1, TAB_LEFT, groups_values[1].f,2,0);
+
+ /* Fill in the group statistics */
+ for ( g=0; g < 2 ; ++g )
+ {
+ struct t_test_proc *ttp = &groups_stats[i][g];
+
+ tab_float(ssb->t, 2 ,i*2+g+1, TAB_RIGHT, ttp->n, 2, 0);
+ tab_float(ssb->t, 3 ,i*2+g+1, TAB_RIGHT, ttp->mean, 8, 2);
+ tab_float(ssb->t, 4 ,i*2+g+1, TAB_RIGHT, ttp->std_dev, 8, 3);
+ tab_float(ssb->t, 5 ,i*2+g+1, TAB_RIGHT, ttp->se_mean, 8, 3);
+ }
+
}
}
/* Initialize the paired values ssbox */
void
-ssbox_paired_init(struct ssbox *this, struct cmd_t_test *cmd unused)
+ssbox_paired_init(struct ssbox *this, struct cmd_t_test *cmd UNUSED)
{
int hsize=6;
/* Populate the ssbox for paired values */
void
-ssbox_paired_populate(struct ssbox *ssb,struct cmd_t_test *cmd unused)
+ssbox_paired_populate(struct ssbox *ssb,struct cmd_t_test *cmd UNUSED)
{
int i;
/* Initialize the independent samples trbox */
void
trbox_independent_samples_init(struct trbox *self,
- struct cmd_t_test *cmd unused)
+ struct cmd_t_test *cmd UNUSED)
{
const int hsize=11;
const int vsize=cmd->n_variables*2+3;
tab_hline(self->t,TAL_1, hsize-2,hsize-1,2);
tab_box(self->t,-1,-1,-1,TAL_1, hsize-2,2,hsize-1,vsize-1);
tab_joint_text(self->t, 2, 0, 3, 0,
- TAB_CENTER,_("Levine's Test for Equality of Variances"));
+ TAB_CENTER,_("Levene's Test for Equality of Variances"));
tab_joint_text(self->t, 4,0,hsize-1,0,
TAB_CENTER,_("t-test for Equality of Means"));
assert(self);
for (i=0; i < cmd->n_variables; ++i)
{
+ int which =1;
+ double p,q;
+ int status;
+ double bound;
+
+ double t;
+ double df;
+
+ double pooled_variance;
+ double std_err_diff;
+ double mean_diff;
+
+ struct t_test_proc *ttp0;
+ struct t_test_proc *ttp1;
+ ttp0=&groups_stats[i][0];
+ ttp1=&groups_stats[i][1];
+
+
tab_text (self->t, 0, i*2+3, TAB_LEFT, cmd->v_variables[i]->name);
tab_text (self->t, 1, i*2+3, TAB_LEFT, _("Equal variances assumed"));
+ df = ttp0->n + ttp1->n - 2.0 ;
+ tab_float (self->t, 5, i*2+3, TAB_RIGHT, df, 2, 0);
+
+ pooled_variance = ( (ttp0->n )*sqr(ttp0->s_std_dev)
+ +
+ (ttp1->n )*sqr(ttp1->s_std_dev)
+ ) / df ;
+
+ t = (ttp0->mean - ttp1->mean) / sqrt(pooled_variance) ;
+ t /= sqrt((ttp0->n + ttp1->n)/(ttp0->n*ttp1->n));
+
+ tab_float (self->t, 4, i*2+3, TAB_RIGHT, t, 8, 3);
+
+
+ which=1; /* get p & q from t & df */
+ cdft(&which, &p, &q, &t, &df, &status, &bound);
+ if ( 0 != status )
+ {
+ msg( SE, _("Error calculating T statistic (cdft returned %d)."),status);
+ }
+
+ tab_float(self->t, 6, i*2+3, TAB_RIGHT, 2.0*(t>0?q:p) , 8, 3);
+
+ mean_diff = ttp0->mean - ttp1->mean;
+ tab_float(self->t, 7, i*2+3, TAB_RIGHT, mean_diff, 8, 3);
+
+
+ std_err_diff = sqrt( sqr(ttp0->se_mean) + sqr(ttp1->se_mean));
+ tab_float(self->t, 8, i*2+3, TAB_RIGHT, std_err_diff, 8, 3);
+
+
+ /* Now work out the confidence interval */
+ q = (1 - cmd->criteria)/2.0; /* 2-tailed test */
+ p = 1 - q ;
+ which=2; /* Calc T from p,q and df */
+ cdft(&which, &p, &q, &t, &df, &status, &bound);
+ if ( 0 != status )
+ {
+ msg( SE, _("Error calculating T statistic (cdft returned %d)."),status);
+ }
+
+ tab_float(self->t, 9, i*2+3, TAB_RIGHT,
+ mean_diff - t * std_err_diff, 8, 3);
+
+ tab_float(self->t, 10, i*2+3, TAB_RIGHT,
+ mean_diff + t * std_err_diff, 8, 3);
+
+
+ {
+ double se2;
+ /* Now for the \sigma_1 != \sigma_2 case */
tab_text (self->t, 1, i*2+3+1,
TAB_LEFT, _("Equal variances not assumed"));
+
+
+ se2 = (sqr(ttp0->s_std_dev)/(ttp0->n -1) ) +
+ (sqr(ttp1->s_std_dev)/(ttp1->n -1) );
+
+ t = mean_diff / sqrt(se2) ;
+ tab_float (self->t, 4, i*2+3+1, TAB_RIGHT, t, 8, 3);
+
+ df = sqr(se2) / (
+ (sqr(sqr(ttp0->s_std_dev)/(ttp0->n - 1 ))
+ /(ttp0->n -1 )
+ )
+ +
+ (sqr(sqr(ttp1->s_std_dev)/(ttp1->n - 1 ))
+ /(ttp1->n -1 )
+ )
+ ) ;
+ tab_float (self->t, 5, i*2+3+1, TAB_RIGHT, df, 8, 3);
+
+ which=1; /* get p & q from t & df */
+ cdft(&which, &p, &q, &t, &df, &status, &bound);
+ if ( 0 != status )
+ {
+ msg( SE, _("Error calculating T statistic (cdft returned %d)."),status);
+ }
+
+ tab_float(self->t, 6, i*2+3+1, TAB_RIGHT, 2.0*(t>0?q:p) , 8, 3);
+
+ /* Now work out the confidence interval */
+ q = (1 - cmd->criteria)/2.0; /* 2-tailed test */
+ p = 1 - q ;
+ which=2; /* Calc T from p,q and df */
+ cdft(&which, &p, &q, &t, &df, &status, &bound);
+ if ( 0 != status )
+ {
+ msg( SE, _("Error calculating T statistic (cdft returned %d)."),status);
+ }
+
+
+ tab_float(self->t, 7, i*2+3+1, TAB_RIGHT, mean_diff, 8, 3);
+
+
+ tab_float(self->t, 8, i*2+3+1, TAB_RIGHT, std_err_diff, 8, 3);
+
+
+ tab_float(self->t, 9, i*2+3+1, TAB_RIGHT,
+ mean_diff - t * std_err_diff, 8, 3);
+
+ tab_float(self->t, 10, i*2+3+1, TAB_RIGHT,
+ mean_diff + t * std_err_diff, 8, 3);
+
+
+
+
+ }
+
}
}
/* Initialize the paired samples trbox */
void
trbox_paired_init(struct trbox *self,
- struct cmd_t_test *cmd unused)
+ struct cmd_t_test *cmd UNUSED)
{
const int hsize=10;
/* Populate the paired samples trbox */
void
trbox_paired_populate(struct trbox *trb,
- struct cmd_t_test *cmd unused)
+ struct cmd_t_test *cmd UNUSED)
{
int i;
}
- tab_float(trb->t, 9, i+3, TAB_RIGHT, p*2.0 , 8, 3);
+ tab_float(trb->t, 9, i+3, TAB_RIGHT, 2.0*(t>0?q:p) , 8, 3);
}
}
- /* Multiply by 2 to get 2-tailed significance */
- tab_float (trb->t, 3, i+3, TAB_RIGHT, q*2.0, 8,3);
+ /* Multiply by 2 to get 2-tailed significance, makeing sure we've got
+ the correct tail*/
+ tab_float (trb->t, 3, i+3, TAB_RIGHT, 2.0*(t>0?q:p), 8,3);
tab_float (trb->t, 4, i+3, TAB_RIGHT, ttp->mean_diff, 8,3);
/* Create , populate and submit the Paired Samples Correlation box */
void
-pscbox(struct cmd_t_test *cmd)
+pscbox(void)
{
const int rows=1+n_pairs;
const int cols=5;
tab_text(table, 3,0, TAB_CENTER | TAT_TITLE, _("Correlation"));
tab_text(table, 4,0, TAB_CENTER | TAT_TITLE, _("Sig."));
-
for (i=0; i < n_pairs; ++i)
{
int which =1;
}
- tab_float(table, 4, i+1, TAB_RIGHT, q*2.0, 8, 3);
-
-
-
+ tab_float(table, 4, i+1, TAB_RIGHT, 2.0*(correlation_t>0?q:p), 8, 3);
}
static int
-compare_var_name (const void *a_, const void *b_, void *v_ unused)
+compare_var_name (const void *a_, const void *b_, void *v_ UNUSED)
{
const struct variable *a = a_;
const struct variable *b = b_;
}
static unsigned
-hash_var_name (const void *a_, void *v_ unused)
+hash_var_name (const void *a_, void *v_ UNUSED)
{
const struct variable *a = a_;
}
}
+
+
+/* Compare two (union value)s */
+int
+value_compare(const union value *a, const union value *b, int width)
+{
+ if (width == 0)
+ return (a->f < b->f) ? -1 : ( a->f > b->f ) ;
+ else
+ return memcmp (a->s, b->s, width);
+}
+
+
+static int
+get_group(const union value *val, struct variable *var)
+{
+ if ( 0 == value_compare(val,&groups_values[0],var->width) )
+ return 0;
+ else if (0 == value_compare(val,&groups_values[1],var->width) )
+ return 1;
+
+ /* Never reached */
+ assert(0);
+ return -1;
+}
+
+
+static void
+group_precalc (void)
+{
+ int i;
+ int j;
+
+ groups_stats = xmalloc(sizeof(group_stats_t) * cmd.n_variables);
+
+ for(i=0; i< cmd.n_variables ; ++i)
+ {
+ for (j=0 ; j < 2 ; ++j)
+ {
+ groups_stats[i][j].sum=0;
+ groups_stats[i][j].n=0;
+ groups_stats[i][j].ssq=0;
+ }
+ }
+
+}
+
+static int
+group_calc (struct ccase *c)
+{
+ int i;
+ union value *gv = &c->data[groups->fv];
+
+ double weight = dict_get_case_weight(default_dict,c);
+
+ gv = &c->data[groups->fv];
+
+ for(i=0; i< cmd.n_variables ; ++i)
+ {
+ int g = get_group(gv,groups);
+ struct t_test_proc *ttp=&groups_stats[i][g];
+ union value *val=&c->data[cmd.v_variables[i]->fv];
+
+ ttp->n+=weight;
+ ttp->sum+=weight * val->f;
+ ttp->ssq+=weight * sqr(val->f);
+ }
+
+ return 0;
+}
+
+static void
+group_postcalc (void)
+{
+ int i;
+ int j;
+
+ for(i=0; i< cmd.n_variables ; ++i)
+ {
+ for (j=0 ; j < 2 ; ++j)
+ {
+ struct t_test_proc *ttp;
+ ttp=&groups_stats[i][j];
+
+ ttp->mean = ttp->sum / ttp->n;
+
+ ttp->s_std_dev= sqrt(
+ ( (ttp->ssq / ttp->n ) - ttp->mean * ttp->mean )
+ ) ;
+
+ ttp->std_dev= sqrt(
+ ttp->n/(ttp->n-1) *
+ ( (ttp->ssq / ttp->n ) - ttp->mean * ttp->mean )
+ ) ;
+
+ ttp->se_mean = ttp->std_dev / sqrt(ttp->n);
+ }
+
+ }
+}
projects / pspp / blobdiff