The portion of the curve being "matched" in every position is that over the X-range 



from O.OlXp through Xp. Be sure to match this X-range of the analyst's curve with the 



corresponding X-range of the Standards. Adopted transforms from this set apply only 



within the limits O.OIX < X <. X . 



p - - p 



MISCELLANEOUS NOTES ON MATCHACURVE 



• There will be cases where the X transform determined from Matchacurve is not 

 sufficiently accurate to suit the analyst's purposes. In such cases, curve-form 

 description procedures beyond the scope of this paper must be used. For example, 

 refer to nonlinear regression in the text by Draper and Smith. 2./ 



, The alternative of using a completely automated X-transform selection system from 

 the Matchacurve family of curves was considered. Such a system was bypassed in 

 favor of the graphic comparison technique, which minimizes constraints on curve 

 selection criteria and is still relatively fast to use. It is important to note 

 that selection criteria vary with analysts, analytical objectives, and data charac- 

 teristics . Our inability even to define applicable criteria commonly used (aside 

 from least squares) discouraged the adoption of complete automation here. 



Draper and H. Smith. Applied regression analysis. New York: Wiley and Sons, 



Inc. 1968. 



7 



