This inverse relationship can be used in estimating (interpolating) a variable ''x''<sub>''i''</sub> from prior estimates of the principal components ''y''<sub>''j''</sub>. The first principal components ''y''<sub>''j''</sub>, j ≤ ''P''<sub>0</sub>, can be estimated by some type of regression procedure (such as kriging), while the higher components ''y''<sub>''j''</sub>, j > ''P''<sub>0</sub>, corresponding to random noise, can be estimated by their respective means. | This inverse relationship can be used in estimating (interpolating) a variable ''x''<sub>''i''</sub> from prior estimates of the principal components ''y''<sub>''j''</sub>. The first principal components ''y''<sub>''j''</sub>, j ≤ ''P''<sub>0</sub>, can be estimated by some type of regression procedure (such as kriging), while the higher components ''y''<sub>''j''</sub>, j > ''P''<sub>0</sub>, corresponding to random noise, can be estimated by their respective means. |