36 Henry Quastler 



EXERCISES 



13. The following table gives the number of times the four possible combinations of two 

 flower colors with two pollen shapes were found : 



Pollen shape 



Flower color : 

 Purple Red 



Long 296 27 



Round I 19 85 



Is there information transmission between these two characters ? 

 14. Define the following functions, and derive their values (in terms of //-functions) 



What is the informational value of the test? 



What is the maximum informational value that any test could give in this situation? 



16. A teletype machine sends 2.3 groups of five binary symbols per second. What is the 

 maximum possible rate of information transmission ? 



17. Same machine as in Exercise (16). All code groups are equiprobable. Error probabili- 

 ties are as follows: symbols nos. 1 and 4 are always received correctly, nos. 2 and 3 are wrong 

 1 1 per cent of the time, no. 5 is wrong 1 per cent of the time. All errors are equiprobable. 

 Compute equivocation and amount of information transmitted. 



18. You are to send 2-bit messages through a channel which has the property that one in 

 five binary symbols is bound to be in error. Construct four sequences of five binary messages 

 which will allow the reconstruction of the original message. What is the efficiency of the code? 



V. ORGANIZATION 



Systems, Structures, Pattern 



A system is an organized whole made up of interrelated parts. Organization 

 is based upon the interrelations between parts. The parts may be strongly or 

 weakly coupled; their effect on each other may be quantitative or qualitative. 



(Z> Kr) 



Fig. 6. A simple communication network 



If two parts are coupled in any fashion, then knowledge of the state of one must 

 imply some information about the state of the other. Accordingly, any interrela- 

 tion can be technically represented as a channel. So, two components of a 

 system can be symbolically represented by a simple communication network of 

 two parts, referred to as two nodes and one channel: 



