Let p1 be the first proportion=192/300=0.64 and p2 the second=117/260=0.45. Since we don't have population stats, we need to work out the standard error (SE) of the difference between p1 and p2, with n1 and n2 being the sample sizes:
SE=sqrt(p1(1-p1)/n1+p2(1-p2)/n2)=sqrt(0.64*0.36/300+0.45*0.55/260)=0.041472 and p1-p2=0.19.
From the confidence level of 95%, we get a=1-0.95=0.05 and the critical probability is 1-a/2=0.975. From this we can read off the z-score for the critical value: 1.96 and compute the margin of error: 1.96*0.041472=0.081285.
Now we can apply the margin of error to p1-p2: 0.19+0.08, confidence of 95% that the difference lies between 0.11 and 0.27.