# Confidence Interval Calculator for Proportions

The sample confidence interval proportion is a binomial proportion in a statistical population. Binomial confidence interval calculation rely on the assumption of binomial distribution. For example, a binomial distribution is the set of various possible outcomes and probabilities, for the number of heads observed when a coin is flipped ten times. This confidence interval calculator for proportions helps to find the sample confidence interval for proportion.

## Sample Confidence Interval for Proportion Calculator

The sample confidence interval proportion is a binomial proportion in a statistical population. Binomial confidence interval calculation rely on the assumption of binomial distribution. For example, a binomial distribution is the set of various possible outcomes and probabilities, for the number of heads observed when a coin is flipped ten times. This confidence interval calculator for proportions helps to find the sample confidence interval for proportion.

Code to add this calci to your website

#### Formula:

Proportion = Frequency of Sample Size/Sample Size
s = √((Proportion x (1-Proportion))/Sample Size)
α = (1-(Confidence Level/100))/2
Margin of Error = s x z
Upper Limit = Proportion + Margin of Error
Lower Limit = Proportion - Margin of Error
**Where,**
z = Z Score of 'α'
### Example:

A sample of size 12 and frequency 10 with confidence interval of 95 %

#### Sample Confidence Interval for Proportion:

Proportion = 10/12

= 0.8333

s = √((0.8333 x (1- 0.8333)) / 12

= 0.107583

α = (1- (95/100))/2

= 0.025

z - score of 'α (0.025)' is 1.96

Margin of Error = s x z

= 0.107583 x 1.96

= 0.2109

Upper Limit = Proportion + Margin of Error

= 0.8333 + 0.2109

= 1.0442

Lower Limit = Proportion - Margin of Error

= 0.8333 - 0.2109

= 0.6225