The correlation between load factor and engine running time is due to the fact that short
shifts (less than five hours) are usually for non-production related work and do not result
in significant loading of the engine. Figure 2 shows that shifts greater than 10 hours do
not exhibit this positive correlation. The positive correlation between load factor and
travel time is really because longer shifts result in longer travel times. This is evidenced
by the lack of statistically significant correlation between load factor and ratio of travel
time (p-value greater than α). Hence the only significant and meaningful correlation is
between load factor and front end operating time and utilization.