Question 1076839
The sample mean is 0.29
one sample proportion 95% CI is 0.29 +/- 1.96*sqrt (0.29*0.71/1200)=0.29+/-1.96*0.130=+/-0.0257
(0.2643, 0.3157)
(0.26, 0.32) to two decimal places.  Calculator confirms.