Lower Bound of a 95 Confidence Interval Calculator
Understanding the lower bound of a 95 confidence interval is crucial in statistics to make informed decisions. It helps us estimate the population parameter with a certain degree of confidence.
How to Use This Calculator
- Enter your sample size.
- Select your desired confidence level (95% or 99%).
- Click ‘Calculate’.
Formula & Methodology
The formula for the lower bound of a confidence interval is:
Lower Bound = Sample Mean – (Z * Standard Error)
Where Z is the Z-score corresponding to the desired confidence level, and Standard Error is calculated as:
Standard Error = Standard Deviation / √Sample Size
Real-World Examples
Data & Statistics
| Sample Size | 95% CI | 99% CI |
|---|---|---|
| 30 | 5.23 | 6.64 |
| 100 | 2.58 | 3.26 |
Expert Tips
- Larger sample sizes result in narrower confidence intervals.
- Higher confidence levels result in wider confidence intervals.
Interactive FAQ
What is a confidence interval?
A confidence interval is a range of values around a sample statistic (like the mean) that is likely to contain the population parameter with a certain degree of confidence.