272 Distribution of numbers of mutants in bacterial populations 



Limiting form of distribution for large numbers 

 Table 2 provides the means of testing the agreement between theoretical and experimental 

 distributions in experiments in which the mean number of mutations per culture is 15 or 

 fewer, and in which a minority of the cultures have more than 64 mutants. To extend 

 Tables 1 and 2 by use of the recurrence relation (9) to cover experiments in which the 

 mean number of mutations per culture considerably exceeds 15, and to subdivide the class 



Table 2. p r 



p r is the probability that a culture shall have r mutants, the average number of mutations which have occurred 

 per culture being m. For values of r greater than 2, the values of p r have been grouped. Thus the numbers 



r=32 



in the column headed ' 17-32' are values of S p r . 



32 



