Statistics, P Value, Bayesian Statistics, Hypothesis Testing, Binomial Distribution.
Normal(mu=p1, var=1/n *p1*(1-p1)). Note that the sampling distribution is centered around the true mean. Example calculation. Given [p1, n], you can know the variance. The 68–95–99.7 rule of thumb is handy here. E.g. if you have n = 400, and p1 = 0.5, then stddev = sqrt(1/400) * 0.5 = 0.025. Then,