chapter  6
Quantitative Scales, Curvilinear Relationships, and Transformations
Pages 62

InChapter6wecontinueourtreatmentofquantitativescales;thatis,scalesthatcantakeon acontinuousrangeofvalues.Weincludeordinal,interval,andratioscales(Section1.3.3), andnotethattheysharetheminimumpropertythatthescalenumbersassignedtotheobjects ordertheobjectswithregardtothemeasuredattribute.Ordinal(rank-order)scaleshaveonly thisproperty,intervalscalesaddthepropertyofequalunits(intervals),andratioscaleshave bothequalintervalsandequalratios,henceatruescalezero.Despitethesedifferencesinthe amountofinformationtheyyield,wefinditconvenienttotreatthemtogether.Tothispointwe havetreatedquantitativevariablesasiftheyhaveonlyalinearrelationshiptothecriterion.We wouldarguethatinsomeresearchproblemstheremaybeothernonlinearaspectsthatshould beusedinadditionto,orinplaceof,thislinearaspect.Thischapterthusaddressesitselftothe questionofhownonlinearrelationshipscanbedetected,represented,andstudiedwithinthe confinesoflinearMRC,bytheuseofmultipleand/ornonlinearaspectsofresearchvariables.

6.1.1WhatDoWeMeanbyLinearRegression?