Construct a confidence interval of the population of proport

Construct a confidence interval of the population of proportion at the given level of confidence.      

X=120, n = 1200, 94% confidence. The upper bound of confidence interval is

Solution

Note that              
              
p^ = point estimate of the population proportion = x / n =    0.1          
              
Also, we get the standard error of p, sp:              
              
sp = sqrt[p^ (1 - p^) / n] =    0.008660254          
              
Now, for the critical z,              
alpha =   0.06
Thus, z(alpha) =    1.554773595        
Thus,              
              
      
upper bound = p^ + z(alpha) * sp =    0.113464734 [ANSWER]