Preface to First Edition - lib

CHAPTER 7Logistic Regression and GeneralisedLinear Models: Blood Screening,Women’s Role in Society, ColonicPolyps, and Driving and Back Pain7.1 IntroductionThe erythrocyte sedimentation rate (ESR) is the rate at which red blood cells(erythrocytes) settle out of suspension in blood plasma, when measured understandard conditions. If the ESR increases when the level of certain proteinsin the blood plasma rise in association with conditions such as rheumaticdiseases, chronic infections and malignant diseases, its determination might beuseful in screening blood samples taken from people suspected of suffering fromone of the conditions mentioned. The absolute value of the ESR is not of greatimportance; rather, less than 20mm/hr indicates a ‘healthy’ individual. Toassess whether the ESR is a useful diagnostic tool, Collett and Jemain (1985)collected the data shown in Table 7.1. The question of interest is whetherthere is any association between the probability of an ESR reading greaterthan 20mm/hr and the levels of the two plasma proteins. If there is not thenthe determination of ESR would not be useful for diagnostic purposes.Table 7.1:plasma data. Blood plasma data.fibrinogen globulin ESR fibrinogen globulin ESR2.52 38 ESR < 20 2.88 30 ESR < 202.56 31 ESR < 20 2.65 46 ESR < 202.19 33 ESR < 20 2.28 36 ESR < 202.18 31 ESR < 20 2.67 39 ESR < 203.41 37 ESR < 20 2.29 31 ESR < 202.46 36 ESR < 20 2.15 31 ESR < 203.22 38 ESR < 20 2.54 28 ESR < 202.21 37 ESR < 20 3.34 30 ESR < 203.15 39 ESR < 20 2.99 36 ESR < 202.60 41 ESR < 20 3.32 35 ESR < 202.29 36 ESR < 20 5.06 37 ESR > 202.35 29 ESR < 20 3.34 32 ESR > 203.15 36 ESR < 20 2.38 37 ESR > 202.68 34 ESR < 20 3.53 46 ESR > 20117© 2010 by Taylor and Francis Group, LLC