We observe a sample proprotion p-hat = 0.3. If the standard deviation of the sampling distribution of p-hat is 0.04, what is the 95% confidence interval for p?

Answer 1

CI=point estimate +- (z)(standard deviation)
CI= 0.3 +- (1.96)(0.04)
CI= 0.3 +- 0.0784
CI= 0.3 - 0.0784
CI= 0.3 + 0.0784

CI= (0.2216, 0.3784)