**See below for Confidence Interval to z-score conversion

**This is the percent of the population

#### Solution

## Sample Size Formula

z : z-score

p : Population proportion

e : Margin of Error

N : Population size

## Confidence Interval to z-Score

99% = 2.58

98% = 2.33

96% = 2.05

95% = 1.96

92% = 1.75

90% = 1.645

85% = 1.44

80% = 1.28

## What is Sample Size?

Sample size is used in statistics (frequently in conducting surveys) to determine the number of observations that should be included in a sample of the population. It is used to determine how many members of a population should be sampled, while trying to ensure that the results are representative of the whole population.

When conducting a survey it is important to keep in mind that not all surveys that are distributed will be completed. The results provided by the calculator on this page provides the minimum number of responses you will need based on the data you provided.