Confidence Interval Lower Bound & Upper Bound Calculator
Confidence intervals are crucial in statistics, providing a range of values within which we can be confident that the true population parameter lies. The lower bound and upper bound of this interval give us a sense of the uncertainty around our estimate.
- Enter your sample size, confidence level, mean, and standard deviation.
- Click ‘Calculate’.
- View your results below the calculator.
The formula for calculating the confidence interval is:
mean ± (z * (std_dev / sqrt(sample_size)))
Where ‘z’ is the z-score corresponding to your confidence level.
- Always use the appropriate z-score for your desired confidence level.
- Ensure your sample size is large enough for accurate results.
- Consider using a t-distribution if your sample size is small.
What is a z-score?
A z-score indicates how many standard deviations an element is from the mean.