TABLE E4.9
Dupont’s EIA Cellular Product’s EIA
True Positive Negative Positive Negative
Positive 15 1 16 0
Negative 2 164 7 1794.10 In a seroepidemiologic survey of health workers representing a spectrum
of exposure to blood and patients with hepatitis B virus (HBV), it was
found that infection increased as a function of contact. Table E4.10
provides data for hospital workers with uniform socioeconomic status at
an urban teaching hospital in Boston, Massachusetts. Calculate the 95%
confidence intervals for the proportions of HBV-positive workers in each
subpopulation.
TABLE E4.10
Personnel Exposure n HBV Positive
Physicians Frequent 81 17
Infrequent 89 7
Nurses Frequent 104 22
Infrequent 126 114.11 Consider the data taken from a study attempting to determine whether
the use of electronic fetal monitoring (EFM) during labor a¤ects the
frequency of cesarean section deliveries. Of the 5824 infants included in
the study, 2850 were electronically monitored and 2974 were not. The
outcomes are given in Table E4.11.
TABLE E4.11
EFM Exposure
Cesarean Delivery Yes No Total
Yes 358 229 587
No 2492 2745 5237
Total 2850 2974 5824(a)Use the data from the group without EFM exposure, calculate the
95% confidence interval for the proportion of cesarean delivery.
(b)Calculate the 95% confidence interval for the odds ratio representing
the relationship between EFM exposure and cesarean delivery.4.12 A study was conducted to investigate the e¤ectiveness of bicycle safety
helmets in preventing head injury. The data consist of a random sample
176 ESTIMATION OF PARAMETERS