Validation of Certain Statistics for Stochastic PERT Networks | ||||
| The Egyptian Statistical Journal | ||||
| Article 8, Volume 36, Issue 2, December 1992, Page 291-306 | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/esju.1992.314867 | ||||
 View on SCiNiTO | ||||
| Author | ||||
| Ibrahim Mousa Abdel-Fattah | ||||
| Abstract | ||||
| This paper uses a least squares regression analysis to verify the well-known PERT estimate of the mean activity time as a weighted average of the optimistic (a), most likely or modal (m) and pessimistic (b) activity times in the classical formula: ûx = ( a + am + b )/6, and the estimate of the standard deviation of activity duration as one-sixth of the range: σx = (b-a)/6. Based on properties of the beta distribution, the paper shows also that there are theoretical grounds for using these estimates for a specified range of modal activity times, because in this range, ûx closely approximates the actual relationship between the mean and the mode. | ||||
| Keywords | ||||
| Beta Distribution; Least Squares Regression Analysis; Mean Activity Time; Modal Activity Time; PERT Estimate | ||||
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