Figure showing results for each of the 351 possible splittings of the read test data DATA-I, where the said results include the absolute difference S between sums of components of the item score vectors in the 2 subtests that result from the splitting, (left panel); inner product S_ρ of the subtest score vectors (middle panel); reliability r_tt computed using the examinee score vectors implied by the current splitting of the test data, in equation (4) (right panel). These results are plotted against the splitting index, which takes values of 1,2,…351 for DATA-I. Our results by minimising S are overplotted in solid lines, on these results, in the right panel. Cronbach alpha for DATA-I is also computed and overplotted upon the computed reliability values in the right panel, in broken lines.