Help on statistics question

Question

The claim is that the proportion of peas with yellow pods is equal to 0.25​ (or 25%). The sample statistics from one experiment include 420 peas with 93 of them having yellow pods. Find the value of the test statistic.

Answer 1

z = (phat - p0)/sqrt(p0*(1-p0)/n)

where n = 420, p0 = 0.25 and phat is sample proportion (93/420).