I don't understand how to solve this. Can someone help me step by step?

Question

A newspaper conducted a statewide survey concerning a proposal to raise taxes in order to prevent budget cuts to education. The newspaper took a random sample (assume it is an SRS) of 500 registered voters and found that 200 would vote to raise taxes. Let p represent the proportion of registered voters in the state that would vote to raise taxes. (Round your answers to 4 decimal places, if needed.)

(a) The standard error for the sample proportion is .

(b) The margin of error for a 96% confidence interval for p is .

Answer 1

The sample proportion is 200/500 = 0.4

The standard error for the sample proportion is sqrt(p*(1-p)/n) = sqrt(0.4 * 0.6/500) = 0.02

z-critical for 96% CI is z score corresponding to 0.98 probability = 2.05

margin of error = z-critical value * standard error = 2.05 * 0.02 = 0.041