RECOMMENDATIONS 



1. Use the method of moments described here if 

 better accuracy than that given by overlays is desired to 

 estimate the moments and to determine whether a sample 

 is gaussian or non-gaussian. 



2. In the probability density analysis of a noise 

 sample, use a range of amplitudes covering at least ±4 

 standard deviations; otherwise large errors in the estimates 

 of the moments will frequently result. 



3. In future applications of the PDA, have the output 

 of the PDA in a digital form rather than a continuous curve, 

 so that the data will be available in a form more suitable 

 for the calculation of the moments of the distribution. 



ADMINISTRATIVE INFORMATION 



Work was performed under SR 004 03 01, Task 8119 

 (NEL L2-4) by members of the Listening Division. The 

 report covers work from January 1962 to June 1963 and 

 was approved for publication 5 November 1964. 



The author wishes to express appreciation to the 

 members of the Listening Division who contributed their 

 time to perform much of the data processing; W. P. de la 

 Houssaye who wrote the computer program; and Elaine 

 Kyle who prepared the data for the computer. Thanks are 

 also extended to Fred Dickson, who prepared the illustra- 

 tions, and to G. M. Wenz, who made many helpful suggestions 

 during the work phase and during the writing of the 

 manuscript. 



