Source of Variation d.f. Pr > F F value
Site 6 0.0001*z 21.57
Speed (Site) 7 0.0001** 5.22
Height (Site) 7 0.0001** 16.58
Speed*Height (Site) 7 0.0168* 2.51
C.V. (%)   80.89  
Mean (mg/m3)   1.035  
zObserved level of significance (Pr > F: *, **) at 0.05, and 0.01 significant effect, C.V.=coefficient of variation, d.f.=degree of freedom
Table 9: Analysis of variance for the PM measured with sticky tape technique at different time intervals when a vehicle was running at three speeds at sites in Mexico and the US.