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Sample size: Precision of regression-based reference limits

Command:Sample size
Next selectConfidence Interval estimation & Precision
Next selectRegression-based reference limits


With this procedure you can calculate the required sample size for the estimation of regression-based reference limits, such as Age-related reference limits, with a specified relative precision (Bellera & Hanley, 2007).

Required input


You plan a study to obtain a 95% reference limit of blood pressure at different ages. For a 90% confidence interval, the desired relative margin of error is 10% compared with a 95% reference range (the middle 90% of observations). The distribution of age of the subjects is uniform.

You enter 95 for reference limit, 90 for confidence interval, 95 for reference range and 10 for relative margin of error. For distribution, you select Uniform distribution.

Precision of regression-based reference limits

Click Calculate.

The minimum required sample size is 377.

See also