# Confidence Interval Calculator.

The Confidence Interval Calculator estimates the confidence interval meaning the margin of error or the accuracy of a given survey with specific sample size, confidence level, with finite of infinite population size and with certain percentage of choosing specific choice. The Confidence Interval Calculator is a useful tool when trying to estimate the margin of error you desire in your research. The Confidence interval represents the percentage in plus or minus for the amount of error that you can tolerate. A safe confidence interval is set to be between 3 and 5 %. Enjoy!

**How does the Confidence Interval Calculator work?**

The Confidence Interval Calculator allows margin of error calculation by requesting the following data fields:

- Confidence level where users can choose the desired confidence level form the drop down list provided with the confidence levels of 50%, 75%, 80%, 85%, 90%, 95%, 97%, 98%, 99%, 99.99%. Each confidence level from the ones provided above has its own Z score associated as follows:

- for confidence level 50% the Z Score is 0.67449;

- for confidence level 75% the Z Score is 1.15035;

- for confidence level 80% the Z Score is 1.28;

- for confidence level 85% the Z Score is 1.44;

- for confidence level 90% the Z Score is 1.645;

- for confidence level 95% the Z Score is 1.96;

- for confidence level 97% the Z Score is 2.17009;

- for confidence level 98% the Z Score is 2.326;

- for confidence level 99% the Z Score is 2.576;

- for confidence level 99.99% the Z Score is 3.29053.

- Sample size meaning the number of people that will be interviewed.
- Population that can be left blank if population in infinite or that can specified with a finite number if the population is finite;
- Pick certain choice % meaning the percentage you expect to register for picking a certain choice from the answers provided;

**How can you use the Confidence Interval Calculator?**

The Confidence Interval Calculator is a useful tool for establishing the right margin of error you want to have on any research and surveys projects.

18 Jan, 2014 | 0 comments | 3256 views#### Leave a Reply

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