Answer :
we have:
p = 0.75
We calculate the confidence interval using this value at 95% confidence level:
[tex]\begin{gathered} CI=p\pm z\sqrt[]{\frac{p(1-p)}{n}} \\ CI=0.75\pm1.96\times\sqrt[]{\frac{0.75(1-0.75)}{12000}} \\ CI=0.75\pm0.0077 \\ CI=\text{0.75+0.0077=0.7577} \\ or \\ CI=0.75-0.0077=0.7423 \end{gathered}[/tex]So, the 95% confidence interval is 74.23% and 75.77%
margin of error is 0.75 x 100 = 75%