For a hypothesis test about a population proportion which "p" values do we use when computing the standard error for the confidence interval? For example if our null "p" value is .5 and our observed sample "p" value is .7. I know that for the test statistic we use the null "p" value to compute the standard error, but is this the same for the confidence interval around our point estimate? For example if we are doing a 95% confidence interval for our observed sample "p" value of 0.7 would I use p = .7 and q = .3 or p = .5 and q = .5 for my standard error calculation for the confidence interval?