Abstract
The attempt to statistically analyze the characteristics of the therbligs with the purpose of improving the accuracy of rating method had encountered various difficulties with respect to the availability of device for experiment and thus the approach had not been employed. This study in which an experimental device was designed to gather and process a large number of data taken from the continuous series of therblig made it possible to employ the abovementioned approach. Some of the basic characteristics concerning the therbligs which were not known to us thus far were made clear as a result of statistical analysis.
