Margin of Error Calculator
Margin of Error Formula
Margin of Error = z * σ/√n
z : z-score
σ : Population Standard Deviation
n : Sample Size
**Note: σ / √n = Standard Error of the Mean
Confidence Interval to z-Score
99% = 2.58
98% = 2.33
96% = 2.05
95% = 1.96
92% = 1.75
90% = 1.645
85% = 1.44
80% = 1.28
What is Margin of Error?
The margin of error is used in statistics (often for conducting surveys or polls) and it provides a way to measure how accurate, or effective, an analysis is based on the results of; 1) a population, 2) a level of desired confidence, and 3) the standard deviation for the results of a given group. It is important to note that the smaller the margin of error is, the more confidence you can have in the analysis; the results are likely to be close to the "average."
Another way to look at margin of error is if a survey was conducted on a sample of the population and there was 95% confidence with a margin of error of 5%, then your results would be within 5% if the total population was surveyed, 95% of the time.