Natural Selection Is Not Evolution.

[coining The Phrase "test Of Significance"] Critical Tests Of This Kind May Be Called Tests Of Significance, And When Such Tests Are Available We May Discover Whether A Second Sample Is Or Is Not Significantly Different From The First.

I Believe That No One Who Is Familiar, Either With Mathematical Advances In Other Fields, Or With The Range Of Special Biological Conditions To Be Considered, Would Ever Conceive That Everything Could Be Summed Up In A Single Mathematical Formula, However Complex.

The So-called Co-efficient Of Heritability, Which I Regard As One Of Those Unfortunate Short-cuts, Which Have Often Emerged In Biometry For Lack Of A More Thorough Analysis Of The Data.

No Isolated Experiment, However Significant In Itself, Can Suffice For The Experimental Demonstration Of Any Natural Phenomenon; For The "one Chance In A Million" Will Undoubtedly Occur, With No Less And No More Than Its Appropriate Frequency, However Surprised We May Be That It Should Occur To Us.

If One In Twenty Does Not Seem High Enough Odds, We May, If We Prefer It, Draw The Line At One In Fifty (the 2 Per Cent. Point), Or One In A Hundred (the 1 Per Cent. Point). Personally, The Writer Prefers To Set A Low Standard Of Significance At The 5 Per Cent. Point, And Ignore Entirely All Results Which Fail To Reach This Level. A Scientific Fact Should Be Regarded As Experimentally Established Only If A Properly Designed Experiment Rarely Fails To Give This Level Of Significance.