“The experiments must be repeat upon numerous individuals or groups; the varieties of reaction to the stimuli must be recorded and analyzed; the representative character of the samples must be known before generalization can be established. This whole procedure may have more in common with the quantitative study of data drawn from common experience than with the procedure of the man who deals with electric currents passing through a vacuum tube. In collecting and analyzing such experimental data they can obtain, the quantitative workers will find their finest, but most exacting opportunities for developing statistical technique—opportunities even finer than are offered by the recurrent phenomena of business cycles.”