*67*

The standard error of a sample proportion can be calculated as:

**Standard error**= √p(1-p) / n

where:

- p is the proportion of successes
- n is the sample size

To find the standard error of a sample proportion, simply enter the necessary values below and then click the “Calculate” button.

Standard error = √p(1-p) / n

Standard error = √0.2(1-0.2) / 23 = **0.083406**