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RADAR AND ARPA MANUAL
It should be noted that the tables give 95% probabil-
ity values. This is necessary because any such error treat-
ment is essentially statistical in its nature and means that
the results must be within the tolerance values on 19 out
of 20 occasions.
It is important to appreciate that even though the data
is analysed by a computer, this does not mean that the
results are perfect. Further, the errors considered in
arriving at these tabulated values do not include 'blun-
ders'
or errors that result from the input of incorrect
data.
Data obtained from the radar, log and gyro compass
will be subject to random variations whic ...