# Confidence Interval of Reference Range Limit Calculator

Online calculator which helps to estimate the confidence interval of a standard reference range limit (LlciLlrr, UlciLlrr) from the standard deviation of a standard reference range limit (SDSRRL).

## Estimate LlciLlrr, UlciLlrr from SDSRRL

#### Result

Online calculator which helps to estimate the confidence interval of a standard reference range limit (LlciLlrr, UlciLlrr) from the standard deviation of a standard reference range limit (SDSRRL).

Code to add this calci to your website  #### Formula:

Lower Limit = m - t0.975,n-1 x √((n+1)/n) x s.d Upper Limit = m + t0.975,n-1 x √((n+1)/n) x s.d SDSRRL = s.d / 2 LlciLlrr = Llrr - t0.975,n-1 x √((n+1)/n) x SDSRRL UlciLlrr = Llrr + t0.975,n-1 x √((n+1)/n) x SDSRRL LlciUlrr = Ulrr - t0.975,n-1 x √((n+1)/n) x SDSRRL UlciUlrr = Ulrr + t0.975,n-1 x √((n+1)/n) x SDSRRL Where, t - Distribution. s.d - Standard Deviation n - Total Count m - Mean LlciLlrr - is the Lower limit of the confidence interval of the Lower limit of the standard reference range UlciLlrr - is the Upper limit of the confidence interval of the Lower limit of the standard reference range LlciUlrr - is the Lower limit of the confidence interval of the Upper limit of the standard reference range UlciUlrr - is the Upper limit of the confidence interval of the Upper limit of the standard reference range SDSRRL - is the standard deviation of the standard reference range limit Llrr - is the Lower limit of the standard reference range Ulrr - is the Upper limit of the standard reference range

Note:
97.5% percentile with (n-1) degrees of freedom corresponds to t0.975,n-1 from the Student's t-distribution table.