Sec. 4.2 



THE NORMAL FREQUENCY DISTRIBUTION 



89 



2 4 6 8 10 12 14 16 18 20 



Number of heads (r orx) 

 (•= binomial; x = normal approximation) 



Figure 4.22^1 . The normal curve fitted to the binomial frequency distribution 

 with » = 20 and p = 1/2. 



2 4 6 8 10 12 14 16 18 20 

 Number of heads (r orx) 

 (• = binomial; x = normal approximation) 



Figure 4.225. Illustration of the relationship between the area under the normal 



curve and the probabilities which can be derived from a binomial distribution 



with p = 1/2 and n = 20. 



