Abstract
It is the purpose of this paper to propose a systematic approach to the setting of each department goal and the selection of plans for the improvement of the system in a business firm. A method of estimating three points like the one used in PERT is applicable to an estimation of activity performance. However, the PERT computations are based on the constant known variance, therefore the above method is used under the condition of α and β-parameters of Beta distribution-known. In the present paper, a generalized method is proposed, in which the variance is estimated through the estimator's degree of confidence to be used under the condition of α and β unknown.
