5 per cent, or l/20th the total area. A ratio as large as 

 1.96 may be considered sufficiently improbable and hence 

 g ' can be assumed to result from a non-gaussian distribution. 

 The sample would therefore be rejected as coming from a 

 gaussian distribution. The value of g s ' therefore depends 

 onf, g ' - 1.96(24///) s. Edgeworth's series would then 

 be used to compute two curves, one with -g 3 ' (for negative 

 kurtosis) and one with +g 3 ' (for positive kurtosis). These 

 curves would represent the limits, at a 5 per cent 

 probability level, within which a sample of N points would be 

 considered as coming from a gaussian distribution. 



Figure 6 shows two curves as they would appear in 

 the overlay. These two curves are the limits for a sample 



0.5 



g' ■ +0.50 



-3 



g' =-0.50 



-2-10 12 



AMPLITUDE IN STANDARD DEVIATION UNITS 



Figure 6. Overlay indicating g 3 ' of +0.50 and of -0.50, 

 A curve having a value of kurtosis as large or larger 

 than these values will be non- gauss i an at a 5 per cent 

 level for a sample of 3 70 points or, e qui val ent 1 y , a 

 bandwidth of about 55 c/s. 



17 



