Construct a confidence interval of the population proportion at the given level of confidence.
x= 240 n= 300 99% confidence

Confidence interval for population proportion is 
sample proportion +/- confidence coefficient*standard error of p 
Sample proportion = p = x/n = 180/300 = 0.6 
Confidence coefficient is the critical value of z for 95% confidence level = 1.96 
Standard error of p = sqrt [p*(1-p)/n] 
= sqrt [0.6*0.4/300] 
= 0.0283 
The CI is 
0.6 +/- 1.96*0.0283 
0.6 +/- 0.055 
lower boundary is 0.6-0.055 = 0.545 
upper boundary is 0.6+0.055 = 0.655 
The CI is (0.545, 0.655)