The standard one-sample proportion test statistic

To test $H_0:p=p_0$ against the alternative $H_1:p\neq p_0$, where p is the population proportion and $p_0$ is a specified value of p. Suppose $P_n$ denotes the sample proportion based on a random sample of size n from the population. The test statistic for testing $H_0:p=p_0$ against $H_1:p\neq p_0$ is given by: