Issue concerning pre-post paired variables

[Marcos Almeida]

Dear fellow members,
-
I hava a dataset with several pre-post variables, I mean, each pair have the same name, plus the suffix "-pre" or "-pos".

Since I need to perform almost a hundred "paired" tests" (t and signed rank), I wonder if there is a code to streamline this process.

In short, something that would recognize identical names (but for the suffix) and perform the tests for each pair of variables.

Below, I share a fraction of the data.

Lots of thanks in advance for any help.

Kind regards

Marcos

[Andrew Musau]

You need to reduce the length of some of your variable names (some are already 34 characters in length). I won't deal with this in the solution that I provide below - here I delete variables whose names exceed 28 characters in length. For ranksum, you need to reshape to a long format. Here is how to extract prefixes.

use pilot, clear
rename IN INN
drop ladoacometido
foreach var of varlist *{
    if length("`var'")>28{
        drop `var'
     }
}
rename *, lower
foreach ending in pre pos{
    qui ds *_`ending'
    local `ending'vars `=ustrregexra("`r(varlist)'", "_`ending'", "")'
}

local all `prevars' `postvars'
local all: list uniq all
keep id -ladoacometido *_pre *_pos
reshape long `all', i(id) j(which) string

foreach var in `all'{
    display "variable = `var'"
    cap noisily ranksum `var', by(which)
}

Res.:

. foreach var in `all'{
  2.
.     display "variable = `var'"
  3.
.     cap noisily ranksum `var', by(which)
  4.
. }
variable = ash_biceps

Two-sample Wilcoxon rank-sum (Mann–Whitney) test

       which |      Obs    Rank sum    Expected
-------------+---------------------------------
        _pos |        5        23.5        27.5
        _pre |        5        31.5        27.5
-------------+---------------------------------
    Combined |       10          55          55

Unadjusted variance       22.92
Adjustment for ties       -1.39
                     ----------
Adjusted variance         21.53

H0: ash_bi~s(which==_pos) = ash_bi~s(which==_pre)
         z = -0.862
Prob > |z| = 0.3886
Exact prob = 0.4683
variable = ash_adutores

Two-sample Wilcoxon rank-sum (Mann–Whitney) test

       which |      Obs    Rank sum    Expected
-------------+---------------------------------
        _pos |        5          26        27.5
        _pre |        5          29        27.5
-------------+---------------------------------
    Combined |       10          55          55

Unadjusted variance       22.92
Adjustment for ties       -2.50
                     ----------
Adjusted variance         20.42

H0: ash_ad~s(which==_pos) = ash_ad~s(which==_pre)
         z = -0.332
Prob > |z| = 0.7399
Exact prob = 1.0000
variable = ash_rotadores

Two-sample Wilcoxon rank-sum (Mann–Whitney) test

       which |      Obs    Rank sum    Expected
-------------+---------------------------------
        _pos |        5          23        27.5
        _pre |        5          32        27.5
-------------+---------------------------------
    Combined |       10          55          55

Unadjusted variance       22.92
Adjustment for ties       -3.47
                     ----------
Adjusted variance         19.44

H0: ash_ro~s(which==_pos) = ash_ro~s(which==_pre)
         z = -1.021
Prob > |z| = 0.3075
Exact prob = 0.4444
variable = ash_flexpunho

Two-sample Wilcoxon rank-sum (Mann–Whitney) test

       which |      Obs    Rank sum    Expected
-------------+---------------------------------
        _pos |        5        25.5        27.5
        _pre |        5        29.5        27.5
-------------+---------------------------------
    Combined |       10          55          55

Unadjusted variance       22.92
Adjustment for ties       -3.47
                     ----------
Adjusted variance         19.44

H0: ash_fl~o(which==_pos) = ash_fl~o(which==_pre)
         z = -0.454
Prob > |z| = 0.6501
Exact prob = 0.9206
variable = cif_b735_1

Two-sample Wilcoxon rank-sum (Mann–Whitney) test

       which |      Obs    Rank sum    Expected
-------------+---------------------------------
        _pos |        5        22.5        27.5
        _pre |        5        32.5        27.5
-------------+---------------------------------
    Combined |       10          55          55

Unadjusted variance       22.92
Adjustment for ties       -2.50
                     ----------
Adjusted variance         20.42

H0: cif_~5_1(which==_pos) = cif_~5_1(which==_pre)
         z = -1.107
Prob > |z| = 0.2685
Exact prob = 0.4286
variable = cif_b760_1

Two-sample Wilcoxon rank-sum (Mann–Whitney) test

       which |      Obs    Rank sum    Expected
-------------+---------------------------------
        _pos |        5          25        27.5
        _pre |        5          30        27.5
-------------+---------------------------------
    Combined |       10          55          55

Unadjusted variance       22.92
Adjustment for ties       -1.39
                     ----------
Adjusted variance         21.53

H0: cif~60_1(which==_pos) = cif~60_1(which==_pre)
         z = -0.539
Prob > |z| = 0.5900
Exact prob = 0.8095
variable = cif_d4452_1

--------------------------------------TRUNCATED----------------------------------------------

variable = fulg_a

Two-sample Wilcoxon rank-sum (Mann–Whitney) test

       which |      Obs    Rank sum    Expected
-------------+---------------------------------
        _pos |        5        29.5        27.5
        _pre |        5        25.5        27.5
-------------+---------------------------------
    Combined |       10          55          55

Unadjusted variance       22.92
Adjustment for ties       -0.28
                     ----------
Adjusted variance         22.64

H0: fulg_a(which==_pos) = fulg_a(which==_pre)
         z =  0.420
Prob > |z| = 0.6742
Exact prob = 0.7222
variable = fulg_b

Two-sample Wilcoxon rank-sum (Mann–Whitney) test

       which |      Obs    Rank sum    Expected
-------------+---------------------------------
        _pos |        5          27        27.5
        _pre |        5          28        27.5
-------------+---------------------------------
    Combined |       10          55          55

Unadjusted variance       22.92
Adjustment for ties       -5.00
                     ----------
Adjusted variance         17.92

H0: fulg_b(which==_pos) = fulg_b(which==_pre)
         z = -0.118
Prob > |z| = 0.9060
Exact prob = 1.0000
variable = fulg_c

Two-sample Wilcoxon rank-sum (Mann–Whitney) test

       which |      Obs    Rank sum    Expected
-------------+---------------------------------
        _pos |        5          27        27.5
        _pre |        5          28        27.5
-------------+---------------------------------
    Combined |       10          55          55

Unadjusted variance       22.92
Adjustment for ties       -0.56
                     ----------
Adjusted variance         22.36

H0: fulg_c(which==_pos) = fulg_c(which==_pre)
         z = -0.106
Prob > |z| = 0.9158
Exact prob = 0.9524
variable = fulg_d

Two-sample Wilcoxon rank-sum (Mann–Whitney) test

       which |      Obs    Rank sum    Expected
-------------+---------------------------------
        _pos |        5          29        27.5
        _pre |        5          26        27.5
-------------+---------------------------------
    Combined |       10          55          55

Unadjusted variance       22.92
Adjustment for ties       -3.33
                     ----------
Adjusted variance         19.58

H0: fulg_d(which==_pos) = fulg_d(which==_pre)
         z =  0.339
Prob > |z| = 0.7346
Exact prob = 0.9206
variable = fulg_h

Two-sample Wilcoxon rank-sum (Mann–Whitney) test

       which |      Obs    Rank sum    Expected
-------------+---------------------------------
        _pos |        5        27.5        27.5
        _pre |        5        27.5        27.5
-------------+---------------------------------
    Combined |       10          55          55

Unadjusted variance       22.92
Adjustment for ties       -5.14
                     ----------
Adjusted variance         17.78

H0: fulg_h(which==_pos) = fulg_h(which==_pre)
         z =  0.000
Prob > |z| = 1.0000
Exact prob = 1.0000
variable = fulg_j1

Two-sample Wilcoxon rank-sum (Mann–Whitney) test

       which |      Obs    Rank sum    Expected
-------------+---------------------------------
        _pos |        5        28.5        27.5
        _pre |        5        26.5        27.5
-------------+---------------------------------
    Combined |       10          55          55

Unadjusted variance       22.92
Adjustment for ties       -4.86
                     ----------
Adjusted variance         18.06

H0: fulg_j1(which==_pos) = fulg_j1(which==_pre)
         z =  0.235
Prob > |z| = 0.8139
Exact prob = 0.8413
variable = fulg_j2

Two-sample Wilcoxon rank-sum (Mann–Whitney) test

       which |      Obs    Rank sum    Expected
-------------+---------------------------------
        _pos |        5        32.5        27.5
        _pre |        5        22.5        27.5
-------------+---------------------------------
    Combined |       10          55          55

Unadjusted variance       22.92
Adjustment for ties       -1.39
                     ----------
Adjusted variance         21.53

H0: fulg_j2(which==_pos) = fulg_j2(which==_pre)
         z =  1.078
Prob > |z| = 0.2812
Exact prob = 0.3333

.

[Marcos Almeida]

Andrew Musau Thank you so much for the code and for your effort to provide this great solution!

My main concern is that I need to perform a paired t test and the signed rank.

[Andrew Musau]

Right. Just a simple modification needed to extract pairs. You then do not need to worry about variable name lengths as no reshape is needed.

use pilot, clear
rename IN INN
drop ladoacometido
rename *, lower
foreach ending in pre pos{
    qui ds *_`ending'
    local `ending'vars `=ustrregexra("`r(varlist)'", "_`ending'", "")'
}

local all `prevars' `posvars'
local all: list uniq all
local s1: list prevars-posvars
local s2: list posvars-prevars
local s `s1' `s2'
local all: list all -s

foreach var in `all'{
    display "variable = `var'"
    cap noisily ttest `var'_pre= `var'_pos
}

Res.:

. foreach var in `all'{
  2. 
.     display "variable = `var'"
  3. 
.     cap noisily ttest `var'_pre= `var'_pos
  4. 
. }
variable = ash_biceps

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
ash_bi~e |       5         2.6     .509902    1.140175    1.184285    4.015715
ash_bi~s |       5           2    .5477226    1.224745    .4792784    3.520722
---------+--------------------------------------------------------------------
    diff |       5          .6          .4    .8944272    -.510578    1.710578
------------------------------------------------------------------------------
     mean(diff) = mean(ash_biceps_pre - ash_biceps_pos)           t =   1.5000
 H0: mean(diff) = 0                              Degrees of freedom =        4

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.8960         Pr(|T| > |t|) = 0.2080          Pr(T > t) = 0.1040
variable = ash_adutores

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
ash_ad~e |       5         2.2    .3741657      .83666    1.161149    3.238851
ash_ad~s |       5           2    .4472136           1     .758336    3.241664
---------+--------------------------------------------------------------------
    diff |       5          .2          .2    .4472136    -.355289     .755289
------------------------------------------------------------------------------
     mean(diff) = mean(ash_adutores_pre - ash_adutores_pos)       t =   1.0000
 H0: mean(diff) = 0                              Degrees of freedom =        4

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.8130         Pr(|T| > |t|) = 0.3739          Pr(T > t) = 0.1870
variable = ash_rotadores

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
ash_ro~e |       5         2.6     .244949    .5477226    1.919913    3.280087
ash_ro~s |       5           2    .4472136           1     .758336    3.241664
---------+--------------------------------------------------------------------
    diff |       5          .6          .4    .8944272    -.510578    1.710578
------------------------------------------------------------------------------
     mean(diff) = mean(ash_rotadores_~e - ash_rotadores_~s)       t =   1.5000
 H0: mean(diff) = 0                              Degrees of freedom =        4

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.8960         Pr(|T| > |t|) = 0.2080          Pr(T > t) = 0.1040
variable = ash_flexpunho

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
ash_fl~e |       5         2.4          .6    1.341641    .7341329    4.065867
ash_fl~s |       5           2    .6324555    1.414214    .2440219    3.755978
---------+--------------------------------------------------------------------
    diff |       5          .4          .4    .8944272    -.710578    1.510578
------------------------------------------------------------------------------
     mean(diff) = mean(ash_flexpunho_~e - ash_flexpunho_~s)       t =   1.0000
 H0: mean(diff) = 0                              Degrees of freedom =        4

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.8130         Pr(|T| > |t|) = 0.3739          Pr(T > t) = 0.1870
variable = cif_b735_1

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
~5_1_pre |       5         2.4          .4    .8944272    1.289422    3.510578
~5_1_pos |       5         1.8    .3741657      .83666    .7611494    2.838851
---------+--------------------------------------------------------------------
    diff |       5          .6     .244949    .5477226   -.0800874    1.280087
------------------------------------------------------------------------------
     mean(diff) = mean(cif_b735_1_pre - cif_b735_1_pos)           t =   2.4495
 H0: mean(diff) = 0                              Degrees of freedom =        4

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.9648         Pr(|T| > |t|) = 0.0705          Pr(T > t) = 0.0352
variable = cif_b760_1

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
cif_b7.. |       5         2.6     .509902    1.140175    1.184285    4.015715
cif_b7.. |       5         2.2    .5830952     1.30384    .5810682    3.818932
---------+--------------------------------------------------------------------
    diff |       5          .4     .244949    .5477226   -.2800874    1.080087
------------------------------------------------------------------------------
     mean(diff) = mean(cif_b760_1_pre - cif_b760_1_pos)           t =   1.6330
 H0: mean(diff) = 0                              Degrees of freedom =        4

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.9111         Pr(|T| > |t|) = 0.1778          Pr(T > t) = 0.0889
variable = cif_d4452_1

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
~2_1_pre |       5         2.8    .5830952     1.30384    1.181068    4.418932
~2_1_pos |       5         2.6     .678233    1.516575    .7169233    4.483077
---------+--------------------------------------------------------------------
    diff |       5          .2          .2    .4472136    -.355289     .755289
------------------------------------------------------------------------------
     mean(diff) = mean(cif_d4452_1_pre - cif_d4452_1_pos)         t =   1.0000
 H0: mean(diff) = 0                              Degrees of freedom =        4

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.8130         Pr(|T| > |t|) = 0.3739          Pr(T > t) = 0.1870
variable = cif_d4452_2

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
~2_2_pre |       5         2.8    .5830952     1.30384    1.181068    4.418932
~2_2_pos |       5         2.6     .678233    1.516575    .7169233    4.483077
---------+--------------------------------------------------------------------
    diff |       5          .2          .2    .4472136    -.355289     .755289
------------------------------------------------------------------------------
     mean(diff) = mean(cif_d4452_2_pre - cif_d4452_2_pos)         t =   1.0000
 H0: mean(diff) = 0                              Degrees of freedom =        4

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.8130         Pr(|T| > |t|) = 0.3739          Pr(T > t) = 0.1870
variable = cif_d4450_1

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
cif_d4.. |       5         2.6     .678233    1.516575    .7169233    4.483077
cif_d4.. |       5           2    .7071068    1.581139    .0367568    3.963243
---------+--------------------------------------------------------------------
    diff |       5          .6     .244949    .5477226   -.0800874    1.280087
------------------------------------------------------------------------------
     mean(diff) = mean(cif_d4450_1_pre - cif_d4450_1_pos)         t =   2.4495
 H0: mean(diff) = 0                              Degrees of freedom =        4

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.9648         Pr(|T| > |t|) = 0.0705          Pr(T > t) = 0.0352
variable = cif_d4450_2

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
~0_2_pre |       5         2.6     .678233    1.516575    .7169233    4.483077
~0_2_pos |       5           2    .7071068    1.581139    .0367568    3.963243
---------+--------------------------------------------------------------------
    diff |       5          .6     .244949    .5477226   -.0800874    1.280087
------------------------------------------------------------------------------
     mean(diff) = mean(cif_d4450_2_pre - cif_d4450_2_pos)         t =   2.4495
 H0: mean(diff) = 0                              Degrees of freedom =        4

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.9648         Pr(|T| > |t|) = 0.0705          Pr(T > t) = 0.0352
variable = cif_d4451_1

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
cif_d4.. |       5           3    .5477226    1.224745    1.479278    4.520722
cif_d4.. |       5         2.4     .678233    1.516575    .5169233    4.283077
---------+--------------------------------------------------------------------
    diff |       5          .6          .4    .8944272    -.510578    1.710578
------------------------------------------------------------------------------
     mean(diff) = mean(cif_d4451_1_pre - cif_d4451_1_pos)         t =   1.5000
 H0: mean(diff) = 0                              Degrees of freedom =        4

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.8960         Pr(|T| > |t|) = 0.2080          Pr(T > t) = 0.1040
variable = cif_d4451_2

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
~1_2_pre |       5           3    .5477226    1.224745    1.479278    4.520722
~1_2_pos |       5         2.4     .678233    1.516575    .5169233    4.283077
---------+--------------------------------------------------------------------
    diff |       5          .6          .4    .8944272    -.510578    1.710578
------------------------------------------------------------------------------
     mean(diff) = mean(cif_d4451_2_pre - cif_d4451_2_pos)         t =   1.5000
 H0: mean(diff) = 0                              Degrees of freedom =        4

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.8960         Pr(|T| > |t|) = 0.2080          Pr(T > t) = 0.1040
variable = cif_e1101_1

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
cif_e1~e |       5         3.4          .4    .8944272    2.289422    4.510578
cif_e1~s |       5           3    .6324555    1.414214    1.244022    4.755978
---------+--------------------------------------------------------------------
    diff |       5          .4     .244949    .5477226   -.2800874    1.080087
------------------------------------------------------------------------------
     mean(diff) = mean(cif_e1101_1_pre - cif_e1101_1_pos)         t =   1.6330
 H0: mean(diff) = 0                              Degrees of freedom =        4

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.9111         Pr(|T| > |t|) = 0.1778          Pr(T > t) = 0.0889
variable = cif_e310_1

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
cif_e3~e |       5           2    .8944272           2    -.483328    4.483328
cif_e3~s |       5         1.8    .9165151     2.04939    -.744654    4.344654
---------+--------------------------------------------------------------------
    diff |       5          .2          .2    .4472136    -.355289     .755289
------------------------------------------------------------------------------
     mean(diff) = mean(cif_e310_1_pre - cif_e310_1_pos)           t =   1.0000
 H0: mean(diff) = 0                              Degrees of freedom =        4

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.8130         Pr(|T| > |t|) = 0.3739          Pr(T > t) = 0.1870
variable = cvmob_velo_ida_lateral

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
cvmob_.. |       4    .7777636    .5408524    1.081705   -.9434701    2.498997
cvmob_.. |       4    .4322929    .2363735    .4727471   -.3199532    1.184539
---------+--------------------------------------------------------------------
    diff |       4    .3454707    .3094388    .6188776   -.6393016    1.330243
------------------------------------------------------------------------------
     mean(diff) = mean(cvmob_velo_ida~e - cvmob_velo_ida~s)       t =   1.1164
 H0: mean(diff) = 0                              Degrees of freedom =        3

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.8272         Pr(|T| > |t|) = 0.3456          Pr(T > t) = 0.1728
variable = cvmob_velo_volta_lateral

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
cvmob_.. |       4    .7388365    .3579694    .7159388   -.4003819    1.878055
cvmob_.. |       4    .5423261    .2564292    .5128584    -.273746    1.358398
---------+--------------------------------------------------------------------
    diff |       4    .1965104    .1048099    .2096198   -.1370415    .5300623
------------------------------------------------------------------------------
     mean(diff) = mean(cvmob_velo_vol~e - cvmob_velo_vol~s)       t =   1.8749
 H0: mean(diff) = 0                              Degrees of freedom =        3

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.9213         Pr(|T| > |t|) = 0.1575          Pr(T > t) = 0.0787
variable = cvmob_acel_ida_lateral

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
cvmob_.. |       4    .0971805    .0411243    .0822487   -.0336955    .2280564
cvmob_.. |       4    .0831097    .0368557    .0737114   -.0341816     .200401
---------+--------------------------------------------------------------------
    diff |       4    .0140707    .0063743    .0127485    -.006215    .0343565
------------------------------------------------------------------------------
     mean(diff) = mean(cvmob_acel_ida~e - cvmob_acel_ida~s)       t =   2.2074
 H0: mean(diff) = 0                              Degrees of freedom =        3

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.9428         Pr(|T| > |t|) = 0.1144          Pr(T > t) = 0.0572
variable = cvmob_acel_volta_lateral

Paired t test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. err.   Std. dev.   [95% conf. interval]
---------+--------------------------------------------------------------------
cvmob_.. |       4    .1799884    .0702435     .140487   -.0435579    .4035346
cvmob_.. |       4    .1331333    .0490312    .0980625    -.022906    .2891726
---------+--------------------------------------------------------------------
    diff |       4    .0468551    .0224453    .0448907    -.024576    .1182862
------------------------------------------------------------------------------
     mean(diff) = mean(cvmob_acel_vol~e - cvmob_acel_vol~s)       t =   2.0875
 H0: mean(diff) = 0                              Degrees of freedom =        3

 Ha: mean(diff) < 0           Ha: mean(diff) != 0           Ha: mean(diff) > 0
 Pr(T < t) = 0.9360         Pr(|T| > |t|) = 0.1281          Pr(T > t) = 0.0640

[Marcos Almeida]

Andrew Musau Wow, Really awesome, thank you so much, I'm feeling so much grateful for your great work!

Lots of thanks.