Question

Problem 7. Obesity An obesity researcher conducted a study to assess whether there was a difference in the proportion (prevalence) of individuals who are obese between males and females. The following data were reported by the researcher. Obese? Gender Yes No Total Male 20 130 150 Female 50 150 200 total 70 280 350 Construct a 95% CI for PF-pm, the difference in population proportion of obesity between females and males. Problem 8. Deep Vein Thrombosis The results of a blinded study assessing the use of plasma D-dimer levels for diagnosing deep venous thrombosis (DVT) in patients hospitalized for stroke rehabilitation reported increased accuracy over the standard procedure involving ultrasound. To test the claims of this research team, an independent researcher conducted a study to determine if there was a difference in the accuracy of diagnosis for DVT between the two methods. The data in the table below summarize the findings of this study. Presence of DVT correctly diagnosed? Diagnostic Test: Plasma D-dimer Ultrasound Yes 85 72 T No 20. 38 Construct a 95% CI for pı - P2, where group1 is the plasma D-dimer and group2 is the ultrasound group

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Answer 1

Data X = no of obseseed male = 20 Xa= no. of obesed Female = 50. Here na no.of males Iso 12= no. of females = 200. P = x - 20 - 01133 P2 = x2 = 5o = 0.250 na 200 - 0.2 24 +12 20tso nitna 2 15o +200 ĝo 1-PE1-0.2 018 70 350 95.1. Confidance internal for Pro-Pm) [ (fr -P) † J 9 (hatt) * 2x2)... 1 1 2) - on I co 133 -0.250) S o 2 . L=0.05 , 412 = 0.025. 1 (0.2) (0.8) ( +11 x 20.025 Y lso. 200.). 2 - 20.025 = .96. (-0.117 + 0.0432X1196) = (-0.117+ 0.0847) (-0.2017,-0.0323) 200 2 are on lower Upper limit= -0.2017 limit = -0.0323

Here x, no. of plasma D-dimer - 85 Xz! no. of Ultrasound = 22 to c a ni= 85+ 20 = 105 12 72 +38 110 P = x = 85 - 0.8095 105 P = x2 = 72 = 0.6545 ₂ llo 5 = 24+ x2 - 85+72 = nitna lost 100 a 21-0.7302 – 0 2628 157 -0.1302 215 95% confidance interval (PI-PL). ! (&= 0.05) ( CP - P2) + 2 på (2 + 1 ) ) 60.8095 20 6845) t / Co. 7302) (0.2628) (1 11 los 110 x 20.25 ) 20.025 -1.96 Coiss I 0.0598 x 1.90) = (0.155 t 0.1171) (0.0318 0.2721) Tower limit = 0.0378 Upper limit= 0.272 1