Rewrite the binomial distribution in its mathematical form. It should appear as a probability being equated to a function with a function of three variables, often called “n,” “k” and “p.”
Match the binomial distribution of interest to its general form and compare the values. The general form is P(X = k) = nCk*p^k*(1-p)^(n-k).
Locate the value that equates to “p.” This is the expected value in estimated proportions. For example, if your binomial distribution is P(X = k) = 10Ck*(1/3)^k*(2/3)^(10-k), it should be clear that p = 1/3 in this equation. Thus, E in estimated proportions is 1/3.