Calculate the margin of error for a survey or poll given sample size and confidence level.
The margin of error tells you how far your survey results might be from the true population value. It depends on the sample size, the estimated proportion, and the desired confidence level.
MOE = z × √(p(1−p) / n)
p = 0.5 gives the maximum (most conservative) margin of error. If you don't know the true proportion, 0.5 is the safest assumption.
Increase the sample size. Quadrupling the sample cuts the margin of error in half.