Main-model error-component estimates (the three marginal-price specifications) are the headline residential-electricity results; the regional Table 3 estimates are exploratory ('regional analysis has not yet led to any conclusive results'). Author preference for the primary specifications || 'As noted above, three marginal prices were computed. The statistical results are given below... The results are almost identical for all three sets of price data' (p.415)
Houthakker, H., P. K.Verleger, Jr. and D. Sheehan (1974): “Dynamic Demand Analysis for Gasoline and Residential Electricity.” American Journal of Agricultural Economics 56(2), 412-418