ttest result and asdoc table not agree.

[Rodrigo Badilla]

Hi all,

I am getting problem with results in asdoc table, p-values in the Word file not agree with stata output. example:

clear all
set more off

sysuse auto

*ssc install asdoc

ttest price, by(foreign)


Two-sample t test with equal variances
------------------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
Domestic |      52    6072.423    429.4911    3097.104    5210.184    6934.662
 Foreign |      22    6384.682    558.9942    2621.915     5222.19    7547.174
---------+--------------------------------------------------------------------
combined |      74    6165.257    342.8719    2949.496    5481.914      6848.6
---------+--------------------------------------------------------------------
    diff |           -312.2587    754.4488               -1816.225    1191.708
------------------------------------------------------------------------------
    diff = mean(Domestic) - mean(Foreign)                         t =  -0.4139
Ho: diff = 0                                     degrees of freedom =       72

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.3401         Pr(|T| > |t|) = 0.6802          Pr(T > t) = 0.6599

asdoc ttest price, by(foreign)

Asdoc t-student table show 2 p-value =0, but not agree with any results:

[Leonardo Guizzetti]

I cannot replicate your problem on my computer. I am running a fully updated Stata 16.1, with the most recent version of -asdoc- (see output below). It looks like your screenshot is for a *one* sample t-test, in which case your p-values would be quite small since they are very far away from the default null hypothesis value of zero. You have however compute a *two* sample -ttest- just above that. Perhaps you have made a mistake in your code.

. which asdoc
*! Version 2.3.4.1: Changes made June 15, 2019: option label added to list command; Fixing bys sum in MacOS

(output omitted)

. asdoc ttest price, by(foreign)

Two-sample t test with equal variances
------------------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
Domestic |      52    6072.423    429.4911    3097.104    5210.184    6934.662
 Foreign |      22    6384.682    558.9942    2621.915     5222.19    7547.174
---------+--------------------------------------------------------------------
combined |      74    6165.257    342.8719    2949.496    5481.914      6848.6
---------+--------------------------------------------------------------------
    diff |           -312.2587    754.4488               -1816.225    1191.708
------------------------------------------------------------------------------
    diff = mean(Domestic) - mean(Foreign)                         t =  -0.4139
Ho: diff = 0                                     degrees of freedom =       72

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.3401         Pr(|T| > |t|) = 0.6802          Pr(T > t) = 0.6599

                    Two-sample t test with equal variances

----------------------------------------------------------------------------------------------------------------
                       |      obs1       obs2      Mean1      Mean2        dif     St_Err    t_value    p_value
-----------------------+----------------------------------------------------------------------------------------
price by foreign       |                                                                                        
                   0 1 |        52         22   6072.423   6384.682  -312.2585    754.449        -.4        .68
----------------------------------------------------------------------------------------------------------------
(note: file Myfile.doc not found)
Click to Open File:  Myfile.doc

[Rodrigo Badilla]

Thanks Leonardo Guizzetti, I did check my asdoc version:

 which asdoc
c:\ado\plus\a\asdoc.ado
*! Attaullah Shah; [email protected]
*! Tenured Associate Professor at the Institute of Management Sciences, Peshawar, Pakistan.
*!-------------------------------------------------------------------------------
*! Version 2.3.7.2 : Changes made on March 19, 2020     : Fixed bug in xtpoisson for irr option
*! Attaullah Shah : Formatted macro: flocal creates a local that is formated for decimal points
*! ltc 1 : List to comma, by Attaullah Shah, May 5, 2018

And I changed to your version:

which asdoc
c:\ado\plus\a\asdoc.ado
*! Version 2.3.4.1: Changes made June 15, 2019: option label added to list command; Fixing bys sum in MacOS

My new output:

Thanks for you reply!
Regards
Rodrigo