## Statistical Significance Calculator

Use this calculator to determine whether two percentages are statistically significantly different or not.

 Number of Surveys – Sample 1 Observed % – Sample 1 (written as a number between 0 and 100; i.e., 70% = 70) Number of Surveys – Sample 2 Observed % – Sample 2 (written as a number between 0 and 100; i.e., 70% = 70) Confidence Interval ± Significance =

## Sample Size to Achieve Desired Error Rate

Use this calculator to determine how many surveys you need to achieve a desired confidence interval (or margin of error). A confidence interval, or margin of error, tells you the range that likely contains the true value of a population. You may have seen it as a plus or minus amount reported with poll results. For example, if your confidence interval is 6, and 70% of your sample picks an answer, you can be sure that if you asked everyone in the population, you would get an answer of between 64% and 76% (70% ± 6%).

N [universe]: The total number of people your sample represents

Confidence Level: A confidence level tells you how often the true percentage of the population falls within the confidence interval. Using a 95% confidence level means you can be 95% certain, and a 99% confidence level means you can be 99% certain that the true percentage of the population is within the confidence interval.

Picking a higher confidence level means your confidence interval will be larger. Picking a lower confidence level means the confidence interval will be smaller.

If you don’t know what to pick, a 95% confidence level is commonly used.

 N [universe] z [confidence interval in decimal form] 95%90%85%80% e [desired error] n [Sample Needed]

## Error Rate Calculator

Use this calculator to determine your confidence interval. A confidence interval, or margin of error, tells you the range that likely contains the true value of a population. You may have seen it as a plus or minus amount reported with poll results. For example, if your confidence interval is 6, and 70% of your sample picks an answer, you can be sure that if you asked everyone in the population, you would get an answer of between 64% and 76% (70% ± 6%).

n [sample]: How many surveys were completed

N [universe]: How many people your sample represents

Confidence Level: A confidence level tells you how often the true percentage of the population falls within the confidence interval. Using a 95% confidence level means you can be 95% certain, and a 99% confidence level means you can be 99% certain that the true percentage of the population is within the confidence interval.

Picking a higher confidence level means your confidence interval will be larger. Picking a lower confidence level means the confidence interval will be smaller.

If you don’t know what to pick, a 95% confidence level is commonly used.

 n [sample] N [universe] Confidence Level: 95%90%85%80% Observed % (written as a number between 0 and 100; i.e., 70%=70) Confidence Interval ±