Table 1

 Ordinary least squares regression results

VariableTotal revenues ($million)Average revenue per machine ($/machine)
EstimateSEp ValueEstimateSEp Value
Plaw−5.6012.7460.044−1158.05745.120.124
Time0.5550.133<0.00195.46036.140.010
Time2−0.0030.0010.003−0.3120.2770.262
Machines0.0020.0020.334−2.7630.434<0.001
Income ($trillion)10.3761.738<0.00110782.43471.61<0.001
Winter−4.3441.160<0.001−1353.200314.80<0.001
n101101
R 2 0.8050.639