anchor.diff:  let sampleP1 = vector [18.;21.;16.;22.;19.;24.;17.;21.;23.;18.;14.;16.;16.;19.;18.;20.;12.;22.;15.;17.;]
   let sampleP2 = vector [22.;25.;17.;24.;16.;29.;20.;23.;19.;20.;15.;15.;18.;26.;18.;24.;18.;25.;19.;16.;]
   
  -Testing.TTest.twoSamplePaired sampleP1 sampleP2
  +let paired = TTest.twoSamplePaired sampleP1 sampleP2
  +
  +(*
  +    The test returns a significant p value:
  +    paired.PValue = 0.00439
  +*)
  +
  +
  +(**
  +Case 4: Two sample t test with unequal variances (Welch test)
  +
  +If you are unsure about the nature of the underlying population, you may ask if the theoretical population distributions 
  +you want to compare do have the same standard deviations. 
  +
  +If not the welch test can serve as a appropriate hypothesis test for mean differences.
  +
  +*)
  +
  +
  +let sampleW1 = vector [0.8;0.9;1.0;1.1;1.2]
  +let sampleW2 = vector [0.8;1.1;1.3;1.5;2.0]
  +
  +let welch = TTest.twoSample false sampleW1 sampleW2
  +
  +(*
  +    The test returns a not significant p value:
  +    welch.PValue = 0.1725626595
  +*)
   
   (**
   <a name="ChiSquareTest"></a>
  
positive.code:     |]
  
  let contrastMatrix = 
      [| [|1.0;-1.0;0.0;0.0;|] ; [|1.0;0.0;-1.0;0.0;|] ; [|1.0;0.;0.0;-1.0;|] ; 
      [|0.0;1.0;-1.0;0.0;|]    ; [|0.0;1.0;0.0;-1.0;|] ;
      [|0.0;0.0;1.0;-1.0;|]
      |]
  
  
negative.code: <a name="PostHoc"></a>
  ##PostHoc
  
  This test uses the data shown for ANOVA.
  *)
  
  
  