

Assessing the Effect of Five Gasoline Properties on Exhaust Emissions from Light-Duty Vehicles certified to Tier-2 Standards
                                       
                       Analysis of Data from EPA Phase 3
                                       
                                       
                                (EPAct/V2/E-89)

                                  APPENDIX  D
                                       
                           Influential Measurements


As described in Section 5.2, individual measurements were designated as "influential" on the basis of their externally-studentized residuals, also known as "studentized-deleted residuals" (r-i).  Specifically, measurements were designated as "influential" if the absolute value of their externally-studentized residual was greater than or equal to 3.5 (| r-i | >= 3.5).
Models used to assess the influence of measurements were run as described in Section 5 of the report (Preliminary Modeling).  No influential measurements were identified for THC, CO, NMOG or NMHC.  Influential measurements identified for NOx and PM are listed below.
 Influential Measurements identified for NOx.


Influential Measurements identified for PM.



