Verification method

- Quantitative analysis -

• MERR (Mean Error) : What is the average forecast error ?
  MERR (`-oo~oo`) =  `1/n sum_(i=1)^n (F_i - O_i )`
• RMSE (Root Mean Square Error) : What is the average magnitude of the forecast errors?
  RMSE (`0~oo`) = $sqrt((1)/(n)sum_(i=1)^(n)(F_i-O_i)^2)$
• CORR (Correlation Coefficient) : How well did the forecast values correspond to the observed values ?
  CORR (`-1~1`) = `( sum (F - bar F )( O - bar O )) / ( sqrt( sum (F - bar F )^2 ) sqrt( sum (O - bar O )^2 ) )`