VGI StatCalculator

CALCULATE STATISTICAL VALIDITY FOR YOUR SURVEY

Determining statistical validity is easy with the VGI StatCalculator. Fill in any three variables. Buttons will appear next to the fields you are able to calculate, and the calculator will tell you the answer for the fourth.

Total Population:
Confidence Level:
Sample Size:
Sampling Error: %

DEFINITIONS:

Sampling error:

The error caused by the selection of a sample instead of conducting a census of the entire population.

Population or universe:

The entire group about whom you are trying to get information.

Confidence level:

Statistical likelihood or probability that the answer you get lies within the confidence interval of an estimate.

Sample size:

The number of objects in the sample.

EXAMPLE:

If you randomly interview a sample of 383 respondents [sample size] from a city of 100,000 [population], 95 times out of 100 [95% confidence level] the answer will be within 5% in either direction of reality [sampling error].

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