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Table 4 Regression statistics for ARIMA time series modeling of percent of high-severity fire per year for yellow pine-mixed conifer forests, fires ≥400 ha 1984 to 2010.

From: Trends in Wildfire Severity: 1984 to 2010 in the Sierra Nevada, Modoc Plateau, and Southern Cascades, California, USA

  Last year in model
  2010 2009 2008 2007 2006 2005 2004
Parameter estimates        
Model variance (sigma squared) 0.0079 0.0078 0.0081 0.0084 0.0090 0.0088 0.0096
Intercept 0.3064 0.2986 0.3020 0.3055 0.3085 0.3009 0.3015
Linear trend 0.0028 0.0034 0.0031 0.0028 0.0026 0.0033 0.0032
Autoregressive function (AR) 1 −0.8560 −0.7972 −0.8108 −0.8302 −0.8031 −0.8228 −0.8169
AR 2 −0.6782 −0.5829 −0.6183 −0.6108 −0.5812 −0.5924 −0.5816
AR 3 −0.5713 −0.4404 −0.4414 −0.4403 −0.4232 −0.4638 −0.4583
AR 4 −0.5686 −0.5388 −0.5272 −0.5345 −0.5170 −0.5196 −0.5161
P (linear) 0.011 0.008 0.019 0.046 0.110 0.056 0.096
P (AR 1) <0.001 0.001 0.002 0.002 0.004 0.004 0.005
P (AR 2) 0.023 0.053 0.051 0.057 0.086 0.079 0.099
P (AR 3) 0.039 0.127 0.135 0.140 0.174 0.139 0.160
P (AR 4) 0.008 0.012 0.016 0.016 0.026 0.026 0.035
Statistics of fit        
Number of observations 27 26 25 24 23 22 21
Number of missing actuals 3 3 3 3 3 3 3
Number of model parameters 6 6 6 6 6 6 6
Mean square error 0.008 0.007 0.008 0.008 0.008 0.008 0.009
Root mean square error 0.088 0.086 0.088 0.089 0.091 0.090 0.092
Mean absolute percent error 25.924 24.491 25.293 26.260 27.334 26.154 27.500
Mean absolute error 0.074 0.071 0.073 0.075 0.078 0.074 0.078
R2 0.379 0.386 0.376 0.386 0.303 0.331 0.330
adjusted R2 0.207 0.205 0.182 0.182 0.054 0.074 0.050
Akaike information criterion −104.805 −100.641 −94.900 −89.444 −83.796 −79.534 −73.745