# Plus Four Confidence Interval for Proportion Calculator

## Plus Four Confidence Interval for Proportion Calculator

Use this calculator to compute the plus four confidence interval for population proportion.

Plus Four Confidence Interval Calculator
Sample Size ($n$)
Number of successes ($k$)
Confidence Level ($1-\alpha$)
Results
Estimate of proportion: ($\hat{p}$)
Standard Error of proportion: ($SE$)
Z-critical value: ($Z_{\alpha/2}$)
Margin of Error: ($E$)
Lower Confidence Limits:
Upper Confidence Limits:

### How to use Plus four method calculator

Step 1 - Enter the sample size

Step 2 - Enter the number of successes

Step 3 - Enter the confidence level

Step 4 - Click on "Calculate" to calculate plus four confidence interval

Step 5 - Click on "Calculate" for Decile Calculator for grouped data

Step 6 - Returns standard error of proportions

Step 7 - Return z critical value

Step 8 - Return margin of error

Step 9 - Return lower confidence limits and upper confidence limits

## Plus Four Confidence Interval Formula

$100(1-\alpha)$% plus four confidence interval for population proportion is

### $\hat{p} - E \leq p \leq \hat{p} + E$

where,

• $\hat{p}=\dfrac{X+2}{n+4}$ is the estimate of population proportion based on plus four rule,
• $E = Z_{\alpha/2} \sqrt{\dfrac{\hat{p}(1-\hat{p})}{n+4}}$ is the margin of error,
• $1-\alpha$ is the confidence coefficient,
• $Z_{\alpha/2}$ is the critical value of $Z$.

## Reference

You can read step by step tutorial on Plus Four Confidence Interval for Proportion, tutorial will help you to understand step by step procedure to construct a plus four confidence interval for population proportion and confidence interval for proportion examples.

Plus Four Confidence Interval for Proportion

Plus Four Confidence Interval for Proportion Examples VRCBuzz co-founder and passionate about making every day the greatest day of life. Raju is nerd at heart with a background in Statistics. Raju looks after overseeing day to day operations as well as focusing on strategic planning and growth of VRCBuzz products and services. Raju has more than 25 years of experience in Teaching fields. He gain energy by helping people to reach their goal and motivate to align to their passion. Raju holds a Ph.D. degree in Statistics. Raju loves to spend his leisure time on reading and implementing AI and machine learning concepts using statistical models.