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The prediction intervals (68%, i.e. approximately ± one standard deviation) for all statistical parameters are evaluated using bootstrap procedure with n = 1000 samples.
Following model calculation we get predicted values zi for training (or test) samples with experimental values yi, i.e. {zi, yi} are pairs of values with i = 1,..,N.
We randomly sample pairs {zi, yi} to form n = 1000 bootstrap sets of the same size as the analyzed set. For each bootstrap set we calculate
statistical parameters and use their respective distributions to determine respective confidence intervals.
Since the intervals are in general non-symmetric with respect to the values calculated for the analyzed sets, the average values are reported.