Confidence Interval
01 Definition
Confidence Interval meaning: A range of values that likely contains the true effect of a change.
A confidence interval reports a result as a range instead of a single number, showing the uncertainty around an estimate. A 95 percent confidence interval means the method captures the true value in about 95 percent of repeated tests. A wide interval signals more uncertainty, often from a small sample.
Also called
Why it matters
How Confidence Interval fits the work
Confidence intervals show how precise a result is, reminding you that a single measured number is an estimate rather than an exact truth.
In context
The variant showed a 4 percent lift with a 95 percent confidence interval of 1 percent to 7 percent, so the true gain is likely positive.
Practical note
If the interval for a lift crosses zero, the change may have no real effect. Report the range, not just the point estimate, when making decisions.