Question 1

What does a 95% confidence interval mean?

Accepted Answer

In repeated sampling, 95% of such intervals would contain the true population mean. For a specific interval, you can interpret it as a range of plausible values given your data.

Question 2

Why do I need standard deviation?

Accepted Answer

Confidence intervals quantify uncertainty using variability. Without a dispersion measure, you cannot estimate the standard error and the interval width.

Question 3

Can confidence intervals be misleading?

Accepted Answer

Yes. The formulas assume appropriate sampling and approximate conditions (like near-normality or large n). Violations can make intervals unreliable.

Confidence Interval Calculator

Related calculators