The mathematical theory of graduation or adjustment , which hitherto has been developed chiefly in connection with the needs of actuarial science, centres round the following problem: A set of numbers u 1 , u 2 , u 3 , … u n is supposed to have been obtained from observations or statistics of some kind. These numbers would represent the values of a variable u x corresponding to the values 1, 2, … n of its argument x , were it not that they are affected by accidental irregularities due to errors… Expand