# STATISTICAL CALCULATORS

## Make common statistical calculations in a simple way. Read the instructions for use in detail.

### SAMPLE SIZE CALCULATOR FOR PROPORTIONS

Calculate the sample size you need when your survey measures a proportion or a percentage (for instance, % of smokers in a population). Using this advanced calculator you will see how error margin, confidence level and sample size are interrelated. More information about the used formulas here.

To use the calculator:

- Enter the size of the universe and the degree of heterogeneity of the population.
- Enter 2 out of the 3 remaining parameters. For instance, if you indicate the sample size and the confidence, margin of error will be calculated.
- Press CALCULATE. The resultant value will be highlighted.