CONTENTS 



INTRODUCTION. .. page 5 

 TEST PROGRAM. . . 7 



Instrumentation. . . 7 



Research Techniques. . . 8 



Data Reduction Techniques. . .14 

 RESULTS... 3 

 CONCLUSIONS. . .3 7 



PD of Ambient Ocean Noise. . .3 7 



PD of Ship Noise. . .37 



Comparison of Test Methods. ..37 

 RECOMMENDATIONS. . .38 

 REFERENCES. ..3 9 

 APPENDIX A: DESCRIPTION OF THE PDA AND ITS 



OPERATION... 41-42 

 APPENDIX B: DETERMINATION OF NUMBER OF DATA 



POINTS OF EACH SAMPLE. . .43-44 



TABLES 



1 Noise Samples Selected for Analysis, by Location. . . page 11 



2 Number of Curves Showing Significant Values of Skewness 



and Kurtosis. . . 31 



3 Locations of Curves Showing Significant Values of Skewness 



and Kurtosis. . . 32 



4 Locations of Curves Showing Skewness and Kurtosis at 1 



Per Cent Probability Level. . . 33 



5 List of Curves for Which Chi-Square Was Computed. . .35 



6 Curves Chosen by Normal Curve Overlay as Being Very 



Closely Gaussian. . .36 



