Genetics, ObstetricsPrecise quantification of smoking during pregnancy is difficult in retrospective studies. Routinely collected blood specimens from newborns for screening purposes may providea lowcost method to objectively measure maternal smoking close to the time of delivery. Serum cotinine is an important biomarker of recent smoking. A study was performedcomparing cotinine levels in dried blood spots in newborns with those in umbilical cord blood (the gold standard) among 486 newborns. The lowest detection limit for driedblood spot cotinine was 3.1 ng/mL. The data in the table below were presented relating dried blood spot cotinine determinations to umbilical cord blood cotininedeterminations.Cotinine Level in Dried Blood (ng/mL) Maternal Active Smoking = yes Maternal Active Smoking = no<3.13.145678910111213≥14Total2000211123217388387221101300010398Suppose a cutoff of ≥ 5 ng/mL is proposed as a criterion for testing positive based on dried blood spot cotinine levels.(a) What is the sensitivity using this cut-point? (Round your answer to four decimal places.)(b) What is the specificity using this cut-point? (Round your answer to four decimal places.)Suppose it is estimated based on a large sample of births that 20% of mothers smoke at the time of delivery.Suppose the screening test for detecting whether a mother smokes at the time of pregnancy is based on a cutoff of ≥ 5 ng/mL using dried blood specimens from thenewborn.(c) What is the probability that a mother smokes at the time of delivery if the dried blood specimen is 2 5 ng/mL? (Round your answer to four decimal places.)(d) What is another name for this quantity?O cumulative incidenceO predictive value negativeO predictive value positiveO receiver operating characteristicO prevalence

Genetics, Obstetrics Precise quantification of smoking during pregnancy is difficult in retrospective studies. Routinely collected blood specimens from newborns for screening purposes may provide a lowcost method to objectively measure maternal smoking close to the time of delivery. Serum cotinine is an important biomarker of recent smoking. A study was performed comparing cotinine levels in dried blood spots in newborns with those in umbilical cord blood (the gold standard) among 486 newborns. The lowest detection limit for dried blood spot cotinine was 3.1 ng/mL. The data in the table below were presented relating dried blood spot cotinine determinations to umbilical cord blood cotinine determinations. Cotinine Level in Dried Blood (ng/mL) Maternal Active Smoking = yes Maternal Active Smoking = no <3.1 387 2 3.1 4 5 6 7 8 9 10 11 12 13 214 Total 2 0 0 0 2 1 1 1 2 3 2 1 73 88 2 1 1 0 1 3 0 0 0 1 0 398 Suppose a cutoff of 25 ng/mL is proposed as a criterion for testing positive based on dried blood spot cotinine levels. (a) What is the sensitivity using this cut-point? (Round your answer to four decimal places.) (b) What is the specificity using this cut-point? (Round your answer to four decimal places.) Suppose it is estimated based on a large sample of births that 20% of mothers smoke at the time of delivery. Suppose the screening test for detecting whether a mother smokes at the time of pregnancy is based on a cutoff of 2 5 ng/mL using dried blood specimens from the newborn. (c) What is the probability that a mother smokes at the time of delivery if the dried blood specimen is 2 5 ng/mL? (Round your answer to four decimal places.) (d) What is another name for this quantity? O cumulative incidence O predictive value negative O predictive value positive O receiver operating characteristic O prevalence

1st Edition

ISBN:9781680331141

Author:HOUGHTON MIFFLIN HARCOURT

Publisher:HOUGHTON MIFFLIN HARCOURT

Chapter4: Writing Linear Equations

Section: Chapter Questions

Problem 14CR