two-var-test.md
In inferr: Inferential Statistics

output from 2 sample variance test is as expected when alternative is less

Code
  ifr_ts_var_test(hsb, read, write, alternative = "less")
Output
                 Variance Ratio Test                 
  --------------------------------------------------
    Group      Obs    Mean     Std. Err.    Std. Dev. 
  --------------------------------------------------
    read      200    52.23      0.72         10.25   
   write      200    52.77      0.67         9.48    
  --------------------------------------------------
   combined    400    52.5       0.49         9.86    
  --------------------------------------------------

             Lower Tail Test           
             ---------------           
        ratio = sd(read) / (write)     
              Ho: ratio = 1            
              Ha: ratio < 1

          Variance Ratio Test          
  ------------------------------------
     F       Num DF    Den DF      p    
  ------------------------------------
   1.1701     199       199      0.8656 
  ------------------------------------

output from 2 sample variance test is as expected when alternative is greater

Code
  ifr_ts_var_test(hsb, read, write, alternative = "greater")
Output
                 Variance Ratio Test                 
  --------------------------------------------------
    Group      Obs    Mean     Std. Err.    Std. Dev. 
  --------------------------------------------------
    read      200    52.23      0.72         10.25   
   write      200    52.77      0.67         9.48    
  --------------------------------------------------
   combined    400    52.5       0.49         9.86    
  --------------------------------------------------

             Upper Tail Test           
             ---------------           
              Ho: ratio = 1            
              Ha: ratio > 1

          Variance Ratio Test          
  ------------------------------------
     F       Num DF    Den DF      p    
  ------------------------------------
   1.1701     199       199      0.1344 
  ------------------------------------

output from 2 sample variance test is as expected when alternative is all

Code
  ifr_ts_var_test(hsb, read, write, alternative = "all")
Output
                 Variance Ratio Test                 
  --------------------------------------------------
    Group      Obs    Mean     Std. Err.    Std. Dev. 
  --------------------------------------------------
    read      200    52.23      0.72         10.25   
   write      200    52.77      0.67         9.48    
  --------------------------------------------------
   combined    400    52.5       0.49         9.86    
  --------------------------------------------------

                  Variance Ratio Test                 
  --------------------------------------------------
          F              Num DF           Den DF      
  --------------------------------------------------
        1.1701            199              199        
  --------------------------------------------------

         Null & Alternate Hypothesis        
  ----------------------------------------
         ratio = sd(read) / (write)       
                Ho: ratio = 1

      Ha: ratio < 1        Ha: ratio > 1    
    Pr(F < f) = 0.8656   Pr(F > f) = 0.1344 
  ----------------------------------------