Figure 6. Data analysis of maize yield: (a) Sum of sine model fitted to the maize data, (b) Sum of sine model of maize yield shifted 3 years to the right and synchronized with the de-trended population data
 
The simple linear regression from R indicates that 50% of the variability of maize production is explained by population. The population estimate (1) is statistically significant with a p-value of 0.000159. The corresponding RMSE is 8.273382 x 10-13. The estimates (0 and 1) that result from the regression of maize onto population give Equation 12 for predictions. The model is statistically significant with a p-value of 0.0001594.