confidence and margin of error

#1
im not sure if im reading this question correctly?

A political action committee is interested in finding out what kind of popular support they might expect on an environmental initiative. similar issues have gotten 91% support. The committee will set up a polling program to assure 95% confidence that the margin of error is less than 0.07.

here is what i have

(1.96)^2*(.91)*(.09)/(.07)^2

=64.20
64.20% is the support they might expect to recieve.
 

JohnM

TS Contributor
#2
64.2 or 65 (rounded up) is the minimum sample size required to estimate the % of voters who will support the initiative within +/- 7%.