FINALLY...got to the dragstrip.....timeslips

heeey....what does this tell me?

pass 3 pass 6 pass 7
RT .792 .6919 .6081
60 1.8901 1.8920 1.8727
330 5.5662 5.5810 5.5249
594 8.0890 8.1071 8.0619
1/8 8.6611 8.6801 8.6798
MPH 78.66 78.53 72.82



The runs are quite consistent with one another, but the last run is 6 mph slower....why???????