5.  given the probability model shown in table 4-9, find out the sequence  a1a1a3 a 2 a 3 a 1 the real value label. 
table 4-9 exercise 5. Exercise 6 the probabilistic model
 
 
  
   
   Letters  |  
   Probability  |  
  
 
   
   A1  |  
   0.2  |  
  
 
   
   A2  |  
   0.3  |  
  
 
   
   A3  |  
   0.5  |  
  
 
  
Solution: The above table indicates : FX (k) =0, K≤0, FX (1) =0.2, FX (2) =0.5, FX (3) =1, k>3.
①A1: using the update formula, you get:
    L (1) =0+ (1-0) Fx (0) =0
    U (1) =0+ (1-0) Fx (1) =0.2
The interval for the label of the sequence a1a1 is [0,0.2]
②A1 : using the update formula, you get:
    L (2) =0+ (0.2-0) Fx (0) =0
    U (2) =0+ (0.2-0) Fx (1) =0.04
The interval for the label of the sequence a1a1 is [0,0.04]
③A3 : using the update formula, you get:
    L (3) =0+ (0.04-0) Fx (2) =0.02
    U (3) =0+ (0.04-0) Fx (3) =0.04
The interval for the label of the sequence a1a1a3 is [0.02,0.04]
④A2 : using the update formula, you get:
    L (4) =0.02+ (0.04-0.02) Fx (1) =0.024
    U (4) =0.02+ (0.04-0.02) Fx (2) =0.03
The interval for the label of the sequence a1a1a3a2 is [0.024,0.03]
⑤A3 : using the update formula, you get:
    L (5) =0.024+ (0.03-0.024) Fx (2) =0.027
    U (5) =0.024+ (0.03-0.024) Fx (3) =0.03
The interval for the label of the sequence a1a1a3a2a3 is [0.027,0.03]
⑥A1 : using the update formula, you get:
    L (6) =0.027+ (0.03-0.027) Fx (0) =0.027
    U (6) =0.027+ (0.03-0.027) Fx (1) =0.0276
the label for the sequence A1A1A3A2A3A1 can be generated is: Tx (A1A1A3A2A3A1) = (0.027+0.0276)/2=0.0273
6.  for the probability model given in table 4-9, decode a sequence with a length of ten labeled 0.63215699 . 
Solution: known FX (k) =0, K≤0, FX (1) =0.2, FX (2) =0.5, FX (3) =1, k>3.
Set U (0) =1,l (0) =0
  ①l (1) =0+ (1-0) Fx (x1-1) =fx (xk-1)
  U (1) =0+ (1-0) Fx (x1) =fx (XK)
when xk=3, 0.63215699 is in the interval [0.5,1];
  ②l (2) =0.5+0.5fx (xk-1)
  U (2) =0.5+0.5fx (XK)
when xk=2, 0.63215699 is in [0.6,0.75];
  ③l (3) =0.6+0.15fx (xk-1)
  U (3) =0.6+0.15fx (XK)
when xk=2, 0.63215699 is in [0.63,0.675];
  ④l (4) =0.63+0.045fx (xk-1)
  U (4) =0.63+0.045fx (XK)
When Xk=1, 0.63215699 is in [0.63,0.639];
  ⑤l (5) =0.63+0.009fx (xk-1)
  U (5) =0.63+0.009fx (XK)
when xk=2, 0.63215699 is in [0.6318,0.6345];
  ⑥l (6) =0.6318+0.0027fx (xk-1)
  U (6) =0.6318+0.0027fx (XK)
when xk=1, 0.63215699 is in [0.6318,0.63234];
  ⑦l (7) =0.6318+0.00054fx (xk-1)
  U (7) =0.6318+0.00054fx (XK)
 When Xk=3, 0.63215699 is in [0.63207,0.63234];
  ⑧l (8) =0.63207+0.00027fx (xk-1)
  U (8) =0.63207+0.00027fx (XK)
when xk=2, 0.63215699 is in [0.632124,0.632205];
  ⑨l (9) =0.632124+0.000081fx (xk-1)
  U (9) =0.632124+0.000081fx (XK)
when xk=2, 0.63215699 is in [0.6321402,0.6321645];
  ⑩l (=0.6321402+0.0000243FX) (xk-1)
  U (Ten) =0.6321402+0.0000243fx (XK)
when xk=3, 0.63215699 is in [0.63215235,0.6321645];
  The resulting sequence is:a3a2a2a1a2a1a3a2a2a3.
Yang Yaju-140705010013-fourth time job