Emulator characteristics.

For each of the outputs, column 2 shows the mean of the design data, obtained from inputs that varied across the normalised range 0..1 given in Table 1. Columns 3-5 show the expectation of emulator output (E*[E[f(x))]), the variance of this expectation Var*[E(f(x))], and coefficient of variation (E*[Var(f(x))]/E*[E[f(x)]]×100) of each emulator, when all of the inputs were assigned a standardised mean of 0.5, and a standardised variance of 0.04 (i.e. 95% confidence intervals of 0.108–0.892). Column 7 shows the Mahanalobis distance between each fitted emulator and an additional 20 test points; a good fit was indicated by a value falling in a distribution with a mean of 20 and a standard deviation of 6.8.Emulator characteristics.