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Estimate corrected age for a preterm baby from chronological age and gestational age at birth, preserving weeks and days.

Estimate conception timing from LMP, due date, conception date, ultrasound dating or IVF transfer and show a wider intercourse window…

Calculate coefficient of variation from a data set with an explicit sample or population standard-deviation choice.

Calculate R squared from observed and predicted values with SSE, SST and negative-result support.

Count exact days to the next birthday and show the age reached, with a disclosed February 29 convention.

Estimate BAC with a transparent Widmark-style model, pure-alcohol calculation and broad uncertainty warning.

Estimate daily and per-feed formula volume from the AAP average weight rule while preserving responsive-feeding and product-mixing instructions.

Calculate a baby’s exact calendar age, completed weeks and total days with explicit date conventions.

Calculate a weighted average from matching value and weight lists with an auditable weighted sum.

Calculate the arithmetic mean, sum and count from a numeric list without silently dropping invalid tokens.