About Confidence Interval Calculator
A confidence interval is a range of values that's likely to include a population parameter with a certain degree of confidence. Our calculator helps you determine this range for population means and proportions, which is essential for statistical analysis and research.
Key Features:
- Calculate confidence intervals for both means and proportions
- Multiple confidence level options (90%, 95%, 99%)
- Different calculation methods for proportions
- Visual representation of the confidence interval
- Detailed calculation steps and formulas
- Mobile-friendly responsive design
Common Applications:
- Academic research and statistical analysis
- Market research and survey analysis
- Quality control and process improvement
- Medical and scientific studies
- Business decision making
Formulas Used:
For Means:
CI = x̄ ± t*(s/√n)
Where:
x̄ = sample mean
t* = critical t-value
s = sample standard deviation
n = sample size
For Proportions (Normal Approximation):
CI = p̂ ± z*√(p̂(1-p̂)/n)
Where:
p̂ = sample proportion
z* = critical z-value
n = sample size