Reference Range Calculation using Normal Distribution

Online calculator which helps to estimate the lower and upper limits of the standard reference range (also known as reference interval) based on normal distribution.

Estimate Lower, Upper Limits of Reference Interval

Calculator
Formula

Online calculator which helps to estimate the lower and upper limits of the standard reference range (also known as reference interval) based on normal distribution.

Code to add this calci to your website Expand embed code

Formula:

Lower Limit = m - t_0.975,n-1 x √((n+1)/n) x s.d Upper Limit = m + t_0.975,n-1 x √((n+1)/n) x s.d Where, t - Distribution. s.d - Standard Deviation n - Total Count m - Mean

Note:
97.5% percentile with (n-1) degrees of freedom corresponds to t_0.975,n-1 from the Student's t-distribution table.