1. Using the lambda, mu, sigma method, the sigma and lambda terms allow the 5th percentile lower limit of normal to be independently calculated throughout the age-height spectrum.
Using the lambda, mu, sigma method, the sigma and lambda terms allow the 5th percentile lower limit of normal to be independently calculated throughout the age-height spectrum. For the FEV1/FVC ratio (above) and for both FVC and FEV1 (not shown), the normal range is wider in young children and in older adults. (From Reference 10, with permission.)‏
Bruce H Culver Respir Care 2012;57:
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