MATHEMATICAL & STATISTICAL TECHNIQUES
SECTION 2 : STATISTICS
Unit 5 : DECISION THEORY
COURSE OF ACTION : ALTERNATIVES OR CHOICES (A1,A2 , A3 and so on)
STATE OF NATURE : OUTCOMES OR SITUATIONS  ( S1,S2 or E1 or E2 and so on)
PAY OFF MATRIX : NET PROFIT TO THE DECISION MAKER
PAY OFF MATRIX
  State of Nature
Alternative S1 S2 S3
A1      
A2      
A3      
A4      
A5      
       
OR
  A1 A2 A3 A4 A5
S1          
S2          
S3          
S4          
REGRET MATRIX (OPPORTUNITY LOSS MATRIX)
  State of Nature
Alternative S1 S2 S3
A1      
A2      
A3      
A4      
A5      
       
PART A : DECISION MAKING UNDER UNCERTAINITY
METHODS FOR DECISION MAKING UNDER UNCERTINITY (VIMP)
1)WHEN PAY OFF MATRIX IS GIVEN 
THREE METHODS/ CRITERIA
1 MAXIMAX
2 MAXIMIN
3 LAPLACE
2)REGRET TABLE IS GIVEN
ONE METHOD
1 MINIMAX
1)WHEN PAY OFF MATRIX IS GIVEN
EXAMPLE 1
FIND THE BEST DECISION USING 
THREE METHODS/CRITERIA
1 MAXIMAX
2 MAXIMIN
3 LAPLACE
PAY OFF MATRIX
Course of Action State of Nature  
Alternative S1 S2 S3 Maximum Minimum AVERAGE   95 25 68.333
A1 25 85 95 95 25 68.33   60 0 33.333
A2 40 0 60 60 0 33.33   65 30 50
A3 65 30 55 65 30 50.00   MAX = 95 MAX = 30  MAX =68.33
        Maximum= 95 Maximum =30 Maximum =68.33  
BEST DECISION BY  CRITERIA
SELECT A1 BY MAXIMAX CRITERIA
SELECT A3 BY MAXIMIN CRITERIA
SELECT A1 BY LAPLACE CRITERIA
EXAMPLE 2
PAY OFF MATRIX
Course of Action State of Nature  
Alternative S1 S2 S3 S4 Maximum Minimum   Average
A1 35 100 38 75 100 35   62
A2 58 95 105 55 105 55   78.25
A3 45 30 91 100 100 30   66.5
        Maximum = 105 Maximum = 55   Maximum = 78.25
BEST DECISION BY  CRITERIA
1 MAXIMAX 
2 MAXIMIN
3 LAPLACE
SELECT A2 BY MAXIMAX CRITERIA
SELECT A2 BY MAXIMIN CRITERIA
SELECT A2 BY LAPLACE CRITERIA
EXAMPLE 3
PAY OFF MATRIX
Course of Action State of Nature Maximum Minimum Laplace
Alternative S1 S2 S3                
A1 65 0 45 65 0 36.67          
A2 0 55 60 60 0 38.33          
A3 76 -15 80 80 -15 47.00          
        Maximum =80 Maximum = 0 Maximum = 47          
BEST DECISION/ OPTIMAL DECISION BY  CRITERIA
1 MAXIMAX 
2 MAXIMIN
3 LAPLACE
BEST DECISION/ OPTIMAL DECISION
SELECT A3 BY MAXIMAX CRITERIA
SELECT  A1 or A2 BY MAXIMIN CRITERIA
SELECT  A3 BY LAPLACE CRITERIA
EXAMPLE 4
Course of Action Alternatives A1 A2 A3 A4
State of Nature S1 65 40 60 20
S2 15 50 -20 40
S3 45 60 70 50
Course of Action State of Nature Maximum Minimum Average
Alternatives S1 S2 S3      
A1 65 15 45 65 15 41.67 65 15 45 65 15 41.667
A2 40 50 60 60 40 50.00 40 50 60 60 40 50
A3 60 -20 70 70 -20 36.67 60 -20 70 70 -20 36.667
A4 20 40 50 50 20 36.67 20 40 50 50 20 36.667
        Maximum =70 Maximum =40 Maximum = 50
BEST DECISION/ OPTIMAL DECISION BY  CRITERIA
MAXIMAX 
MAXIMIN
LAPLACE
BEST DECISION/ OPTIMAL DECISION
SELECT   A3 BY MAXIMAX CRITERIA
SELECT  A2 BY MAXIMIN CRITERIA
SELECT   A2 BY LAPLACE CRITERIA
DIV A
FIND THE REGRET TABLE AND THE BEST DECISION USING MINIMAX METHOD
CRITERIA FOR DECISION IS MINIMAX
EX 1
PAY OFF MATRIX TO MAKE REGRET TABLE
STEP 1 Course of Action State of Nature STEPS
Alternative S1 S2 S3 1) FIND THE MAXIMUM VALUE IN EACH STATE OF NATURE
A1 25 85 95 2) SUBSTRACT THIS MAXIMUM VALUE FROM EACH VALUE UNDER THE SAME STATE OF NATURE
A2 40 0 60
A3 65 30 55 After making Regret table
        3) Select Max for each Alternative (Amongst the State of Nature)
      4) Then choose Minimum value amongst this
STEP 2 REGRET TABLE
Course of Action State of Nature
Alternative S1 S2 S3 MAXIMUM
A1 40 0 0 40
A2 25 85 35 85
A3 0 55 40 55
         
MINIMUM = 40
STEP 3 BEST DECISION USING MINIMAX REGRET CRITERIA IS 
TO SELECT   A1 
DIV  D
EX 2 FIND THE BEST DECISION USING MINIMAX CRITERIA
PAY OFF MATRIX
Course of Action State of Nature  
Alternative S1 S2 S3 S4
A1 35 100 38 75
A2 58 95 105 55
A3 45 30 91 100
 
SOLUTION
REGRET MATRIX
Course of Action State of Nature              
Alternative S1 S2 S3 S4 MAXIMUM            
A1 23 0 67 25 67            
A2 0 5 0 45 45            
A3 13 70 14 0 70            
MINIMUM = 45
BEST DECISION USING MINIMAX CRITERIA IS 
TO SELECT   A2 BY MINIMAX CRITERIA
EXAMPLE 3
Find the best decision by Using
MAXIMAX 
MAXIMIN
LAPLACE
MINIMAX REGRET METHOD
PAY OFF MATRIX          
Course of Action State of Nature            
Altenative S1 S2 S3 S4 Maximum Minimum Average Average          
A1 25 30 150 80 150 25   71.25          
A2 45 120 50 130 130 45   86.25          
A3 60 100 0 -10 100 -10   37.5          
A4 40 60 65 25 65 25   47.5          
                           
          MAXIMUM =150 MAXIMUM = 45   Maximum =86.25
Find the best decision using
1 MAXIMAX 
2 MAXIMIN
3 LAPLACE
4 MINIMAX REGRET CRITERIA
1 BEST DECISION USING MAXIMAX CRITERIA IS A1
2 BEST DECISION USING MAXIMIN CRITERIA IS A2
3 BEST DECISION USING LAPLACE CRITERIA IS A2
BEST DECISION/ OPTIMAL DECISION
SELECT   A1 BY MAXIMAX CRITERIA
SELECT   A2 BY MAXIMIN CRITERIA
SELECT   A2 BY LAPLACE CRITERIA
PAY OFF MATRIX
Course of Action State of Nature  
Altenative S1 S2 S3 S4
A1 25 30 150 80
A2 45 120 50 130
A3 60 100 0 -10
A4 40 60 65 25
REGRET MATRIX
Course of Action State of Nature  
Altenative S1 S2 S3 S4 MAXIMUM          
A1 35 90 0 50 90          
A2 15 0 100 0 100          
A3 0 20 150 140 150          
A4 20 60 85 105 105  
 
MINIMUM = 90
BEST DECISION IS TO SELECT   A1 BY MINIMAX CRITERIA
EXAMPLE 4
Find the best decision using
MAXIMIN 
MAXIMAX
LAPLACE
MINIMAX REGRET CRITERIA  
PAY OFF MATRIX
STATE OF NATURE A1 A2 A3          
S1 25 -10 -125  
S2 400 440 400  
S3 650 740 750  
         
COURSE OF ACTION  S1 S2 S3
A1 25 400 650
A2 -10 440 740
A3 -125 400 750
PAY OFF MATRIX
STATE OF NATURE                  
COURSE OF ACTION  S1 S2 S3 Minimum MAXIMUM Average        
A1 25 400 650 25 650 358.3333333        
A2 -10 440 740 -10 740 390        
A3 -125 400 750 -125 750 341.6666667        
MAX= 25 MAX = 750 MAX = 390        
       
       
BEST DECISION/ OPTIMAL DECISION        
SELECT   A1 BY MAXIMIN CRITERIA        
SELECT   A3 BY MAXIMAX CRITERIA        
SELECT   A2 LAPLACE CRITERIA
PAY OFF MATRIX
STATE OF NATURE    
COURSE OF ACTION  S1 S2 S3
A1 25 400 650
A2 -10 440 740
A3 -125 400 750
REGRET MATRIX
STATE OF NATURE    
COURSE OF ACTION  S1 S2 S3 MAXIMUM
A1 0 40 100 100
A2 35 0 10 35
A3 150 40 0 150
Minimum = 35
BEST DECISION IS TO SELECT   A2 BY MINIMAX CRITERIA
DIV C