Question 1100467
90% CI half interval is 1.645*sqrt(0.34375*0.65625)/800; 0.34375 is 275/800.
=1.645*0.0168
0.0276
the mean is 0.34375
The CI is the mean +/- the half interval
(0.316, 0.371)We are 90% confident that the true proportion, which we don't know and never will lies in this interval.  All values in this interval are plausible.