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Table 13. Regressions-fiscal year vs. rice EROI.Regression r^2 value Adjusted r (^2) value p-value Residual sum of squares Equation
Linear 0.01 - 0.10 0.7245 3.77 y = 48.9 - 0.02243x
Quadratic 0.82 0.77 0.0011 0.70 y = 240,191 − 239.7x + 0.0598x^2
Cubic 0.86 0.80 0.0023 0.54 30.67xy = −40,899,374 + 61,347x (^2) + 0.005112x 3 −^
Quartic 0.89 0.81 0.0054 0.43
y = − 25,390,309,936 +
50,659,130x − 37,903x^2 + 12.6x^3
− 0.001572x^4
3.2. Crop Output
Both the rice and wheat crops follow a similar pattern of decreasing output at the beginning of the
study period followed by a steady increase during the rest of the study period. Over the course of the
study period, wheat output increased by 34.6% (31.9% if measured from 2002), and rice by 48.2%
(80.3% if measured from 2002) (Figure 3).
Figure 3. Energy output from wheat and rice produced in Pakistan and the percentage
change in the output from the previous year (1999–2009). Percentage change figures at the
top of the figure are for wheat and in the middle of the figure for rice.
0
20
40
60
80
100
120
0
50
100
150
200
250
300
350
400
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Wheat
Rice
18.0% - 9.7% - 4.2% 5.2% 1.6% 10.8% - 1.6% 9.5% -10.0%
10.3% - 6.8% - 20.1% 15.4% 8.2% 3.7% 10.3% - 1.8% 2.5%
Wheat output (PJ)25.5%
Rice output (PJ)
Time (fiscal years)