If there is only one group, then the null tested is that the
underlying probability of success is p , or .5 if p is
not given. The alternative is that the probability of success is less
than, not equal to, or greater than p or , respectively, as
specified by alternative . A confidence interval for the
underlying proportion with confidence level as specified by
and clipped to * [0,1]* is returned. Continuity
correction is used only if it does not exceed the difference between
sample and null proportions in absolute value. The confidence interval
is computed by inverting the score test.