2 variables x and y with value of 1 or 0, both are measured from same subject at same time. The data has 100 records. the interest is the overall proportion of value 1. Assume x has 60 records of 1, y has 30 records of 1. then, the overall proportion of 1 is (60+30)/(100+100). X and Y are correlated because they are from same subject. How to calculate the 95% confidence interval of the overall proportion?