# Confidence Interval Calculator (1 or 2 means)

## Introduction

The Confidence Interval Calculator is a handy tool that allows you to determine the range within which the true population mean is likely to fall, based on a sample mean, standard deviation, and a chosen confidence level. It’s a valuable resource for statisticians, researchers, and anyone dealing with data analysis.

## How to Use

1. Enter the sample mean (X).
2. Choose the confidence level by selecting a percentage option.
3. Input the standard deviation (s).
4. Enter the number of samples (n).
5. Click the “Calculate” button to find the confidence interval.

## Formula

The confidence interval is calculated using the following formula:

Where:

• is the sample mean.
• is the Z-score corresponding to the chosen confidence level.
• is the standard deviation.
• is the number of samples.

## Example

Suppose you have a sample mean (X) of 50, a confidence level of 95%, a standard deviation (s) of 5, and 100 samples (n). The formula yields a confidence interval of , resulting in a confidence interval of 49.02 to 50.98.

## FAQs

What is a confidence interval?

A confidence interval is a range of values within which the true population mean is likely to lie with a certain level of confidence.

How do I choose the appropriate confidence level?

Common confidence levels include 90%, 95%, and 99%. The choice depends on the desired level of certainty in your estimation.

What is the Z-score, and how do I find it?

The Z-score corresponds to the chosen confidence level and can be found using a standard normal distribution table or a calculator.

## Conclusion

The Confidence Interval Calculator simplifies the process of estimating population parameters with a specified level of confidence. It provides valuable insights for decision-making, hypothesis testing, and drawing meaningful conclusions from your data.