PERT basics – what is PERT and how is it characterized? Choose the most complete description of the Program Evaluation and Review Technique (PERT).

Introduction / Context:
PERT (Program Evaluation and Review Technique) is a foundational project management tool that models uncertainty in activity durations. Exams often ask for its key characteristics to distinguish it from CPM (Critical Path Method).

Given Data / Assumptions:

• PERT treats activities between events and represents networks as event-oriented diagrams.
• Activities have probabilistic durations captured by three estimates.
• PERT saw early adoption in complex R&D projects where uncertainty is high.

Concept / Approach:
PERT uses three duration estimates—optimistic (to), most likely (tm), and pessimistic (tp)—to compute an expected time te and variance for each activity, supporting schedule risk assessment and probability of meeting deadlines.

Step-by-Step Solution:
Identify the core: event-oriented network focusing on uncertainty.Recognize the three-time-estimate model: te = (to + 4*tm + tp) / 6.Recall its classic application context: R&D and innovative projects.Hence, every statement (a–d) correctly describes PERT → choose 'All the above'.

Verification / Alternative check:
Compare PERT to CPM: CPM uses deterministic durations and cost–time tradeoffs; PERT emphasizes stochastic times and event orientation.

Why Other Options Are Wrong:
Picking only one feature under-represents PERT; the method includes all listed attributes.

Common Pitfalls:
Confusing activity-on-node vs event-on-node conventions; PERT historically used event-oriented representation, though modern tools also allow activity-on-node with PERT estimates.

Final Answer:
All the above