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Analytical Chemistry & Spectroscopy

Confidence Interval

The range within which the true value of a measured quantity is expected to lie with a stated probability.

Formula / equation μ = x̄ ± ts / √n
Unit Various

In depth

The interval is calculated from the mean, the standard deviation and a Student's t value chosen for the desired confidence level and the number of degrees of freedom. Reporting an interval rather than a bare number makes the reliability of a result explicit.

Examples in the real world

Reporting a concentration as 0.1043 ± 0.0008 M at the 95% confidence level.