Decision Theory:
Stages of Decision-making process:
1- Study of decision environment and expected states
 of nature.
2- Determine available alternatives or acts.
3- Construct pay-off matrix (or decision table).
4- Select the best alternative (optimum).

Cases of decision-making:
1- Decision under certainty.
2- Decision under uncertainty. (Laplace criterion,
   Maximax-optimism criterion, 
   Maximin-pessimism criterion,
  Hurwiz Criterion, Savage criterion-Minimax regret) 
3- Decision under risk.
  (Expected Monetary value EMV criterion,
   Expected Opportunity Loss EOL criterion,
   Maximum Likelihood criterion)