730 



BELL SYSTEM TECHNICAL JOURNAL 



and 



/32' = 3. 



Also let us assume that the size of the sample n for which the limits 

 are to be established is 1000 and that we wish to establish limits upon 

 the basis of a probability P= .997. 



ARITHMETIC MEAN 

 X 



STANDARD DEVIATION 



SKEWNESS 

 K 



KURTOSIS 

 Pa 



CHI SQUARE 



A V 

 LIMIT 



SAMPLE NUMBER 



SAMPLE SIZE 



UNIVERSE 



Fig. 6 



The nomogram of Fig. 4 gives us immediately that c = 3.0 for 

 P = .997. Hence we enter the nomogram of Fig. 5 on the c scale 

 c = 3.0. The best way in which all four limits can be found by using 

 the nomogram of Fig. 5 is then as follows, where the limits are set in 

 the order Lf, L^^f, Lx', and L„'. Join the point n = 1000 on the n scale 



