ttest.md
In inferr: Inferential Statistics

output from one sample t test is as expected when alternative is less

Code
  ifr_os_t_test(hsb, write, mu = 50, alternative = "less")
Output
                                One-Sample Statistics                               
  ---------------------------------------------------------------------------------
   Variable    Obs     Mean     Std. Err.    Std. Dev.    [95% Conf. Interval] 
  ---------------------------------------------------------------------------------
    write      200    52.775     0.6702       9.4786         -Inf     53.8828   
  ---------------------------------------------------------------------------------

                                   Lower Tail Test                                 
                                   ---------------

                                 Ho: mean(write) >=50                              
                                  Ha: mean(write) <50                               
  --------------------------------------------------------------------------------
   Variable      t      DF       Sig       Mean Diff.    [95% Conf. Interval] 
  --------------------------------------------------------------------------------
    write      4.141    199    0.99997       2.775          -Inf      3.8828   
  --------------------------------------------------------------------------------

output from one sample t test is as expected when alternative is greater

Code
  ifr_os_t_test(hsb, write, mu = 50, alternative = "greater")
Output
                                One-Sample Statistics                               
  ---------------------------------------------------------------------------------
   Variable    Obs     Mean     Std. Err.    Std. Dev.    [95% Conf. Interval] 
  ---------------------------------------------------------------------------------
    write      200    52.775     0.6702       9.4786       51.6678      Inf     
  ---------------------------------------------------------------------------------

                                   Upper Tail Test                                 
                                   ---------------

                                 Ho: mean(write) <=50                              
                                 Ha: mean(write) >50                                
  --------------------------------------------------------------------------------
   Variable      t      DF       Sig       Mean Diff.    [95% Conf. Interval] 
  --------------------------------------------------------------------------------
    write      4.141    199    0.00003       2.775         1.6678      Inf     
  --------------------------------------------------------------------------------

output from one sample t test is as expected when alternative is both

Code
  ifr_os_t_test(hsb, write, mu = 50, alternative = "both")
Output
                                One-Sample Statistics                               
  ---------------------------------------------------------------------------------
   Variable    Obs     Mean     Std. Err.    Std. Dev.    [95% Conf. Interval] 
  ---------------------------------------------------------------------------------
    write      200    52.775     0.6702       9.4786       51.4537    54.0969   
  ---------------------------------------------------------------------------------

                                    Two Tail Test                                  
                                   ---------------

                                 Ho: mean(write) ~=50                              
                                 Ha: mean(write) !=50                               
  --------------------------------------------------------------------------------
   Variable      t      DF       Sig       Mean Diff.    [95% Conf. Interval] 
  --------------------------------------------------------------------------------
    write      4.141    199    0.00005       2.775         1.4537     4.0969   
  --------------------------------------------------------------------------------

output from one sample t test is as expected when alternative is all

Code
  ifr_os_t_test(hsb, write, mu = 50, alternative = "all")
Output
                                One-Sample Statistics                               
  ---------------------------------------------------------------------------------
   Variable    Obs     Mean     Std. Err.    Std. Dev.    [95% Conf. Interval] 
  ---------------------------------------------------------------------------------
    write      200    52.775     0.6702       9.4786       51.4537    54.0969   
  ---------------------------------------------------------------------------------

                                 Ho: mean(write) ~=50

          Ha: mean < 50              Ha: mean ~= 50               Ha: mean > 50        
           t = 4.141                   t = 4.141                   t = 4.141         
         P < t = 0.99997            P > |t| = 0.00005            P > t = 0.00003