▁his ▁innov ative ▁books : ▁The ▁Arr ang ement ▁of ▁Field ▁Exper iments ▁( 1 9 2 6 ) ▁and ▁The ▁Design ▁of ▁Exper iments ▁( 1 9 3 5 ). ▁ ▁Much ▁of ▁his ▁pione ering ▁work ▁de alt ▁with ▁agricult ural ▁applications ▁of ▁statistical ▁methods . ▁ ▁As ▁a ▁m und ane ▁example , ▁he ▁described ▁how ▁to ▁test ▁the ▁lady ▁t ast ing ▁tea ▁hypothesis , ▁that ▁a ▁certain ▁lady ▁could ▁distinguish ▁by ▁flav our ▁alone ▁whether ▁the ▁milk ▁or ▁the ▁tea ▁was ▁first ▁placed ▁in ▁the ▁cup . ▁These ▁methods ▁have ▁been ▁broad ly ▁adapted ▁in ▁bi ological , ▁psych ological , ▁and ▁agricult ural ▁research . ▁ ▁Com parison ▁In ▁some ▁fields ▁of ▁study ▁it ▁is ▁not ▁possible ▁to ▁have ▁independent ▁measurements ▁to ▁a ▁trace able ▁met ro log y ▁standard . ▁ ▁Compar isons ▁between ▁treat ments ▁are ▁much ▁more ▁valuable ▁and ▁are ▁usually ▁prefer able , ▁and ▁often ▁compared ▁against ▁a ▁scientific ▁control ▁or ▁traditional ▁treatment ▁that ▁acts ▁as ▁bas eline . ▁ ▁Random ization ▁Random ▁assignment ▁is ▁the ▁process ▁of ▁assigning ▁individuals ▁at ▁random ▁to ▁groups ▁or ▁to ▁different ▁groups ▁in ▁an ▁experiment , ▁so ▁that ▁each ▁individual ▁of ▁the ▁population ▁has ▁the ▁same ▁chance ▁of ▁becoming ▁a ▁particip ant ▁in ▁the ▁study . ▁The ▁random ▁assignment ▁of ▁individuals ▁to ▁groups ▁( or ▁conditions ▁within ▁a ▁group ) ▁distingu ishes ▁a ▁rig orous , ▁" true " ▁experiment ▁from ▁an ▁observ ational ▁study ▁or ▁" qu asi - ex periment ". ▁There ▁is ▁an ▁extensive