as computed from the histogram is given beside the histogram. 
Bax and P.E. are reliable and theoretically definite statis- 
tical quantities obtained from wave records. These points will 
be considered in more detail later. 
The remaining histogram in figure 14 was obtained from a 
pressure record which was taken by a pressure recorder in 30.5 
feet of water (mean low water) offshore from Long Branch, New 
Jersey. It was obtained in October 1951, while an east coast 
storm passed Long Branch just a short distance out over the 
ocean. This histogram is more nearly distributed according to 
the Gaussian law than the height record was. In fact, 43 out 
of 100 times at random, this histogram could have come from a 
normal distribution. The better agreement can be explained on 
the basis of the fact that the second order non-linear terms die 
out more rapidly with depth. Consequently in the pressure re- 
cord the higher ridges and shallower troughs which were at the 
surface are less accentuated. From these histograms, EY 
max 
has been computed which is analogous to the quantity Ea in 
the height record. However, P.K. cannot be computed from E ° 
sities max 
P.E. can be computed if either BC pe) or (AH) is known, 
and if a certain linear operator is applied to EC) in order 
to get the value of E,., which applies to the free surface (see 
x 
the discussion of pressure records in a later chapter). 
A number of other samples of points equally spaced in time 
were picked from this same pressure wave record. Of these, 
several values of Chi Square were so high that they were not 
in the tables. Other values were quite reasonable, and the 
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