From the table it is seen that the waves between heights of zero and 

 5.6 were simply not observed although there should have been about 

 five of them in a sample of fifty values under the assumption that the 

 true mean was 15.5 feet. Also the mean of 15.5 feet implies that there 

 should have been five waves greater than 26.6 feet and only one such 

 wave was actually observed. 



Now, the heights of all waves in the original sample which are greater 

 than 10 feet can be averaged. The result is an average of 17.1 feet, 

 and by the application of the results given above it follows that a better 

 estimate of the significant height is 20.9 feet and that a better estimate 

 of the average height of all waves is 13.1 feet. The results are summa- 

 rized in table 6. 



Table 6 



Corrected data on the basis of the theory of truncated distributions 



Average of heights greater than or equal to 10 ft. = 17.1 ft. 



Significant height = 20.9 ft. 

 True average height = 13.1 ft. 



Limits 



10 



Theoretical 

 Frequency 



26 



With a lower true average height the predicted number of waves 

 with large height values agrees much better with the observations. 

 Or, stated another way, table 6 agrees with the theory much better 

 at the high end of the distribution than table 5. Another important 

 point to note is that of the twenty- six waves less than ten feet in height, 

 which in all probability actually passed during the time of observation, 

 only 9 were observed. The effect of this omission must be to increase 

 the computed average of the uncorrected results to a value greater than 

 the true average. 



25 



