1) (Five parts 23 marks in total) Persistent patent ductus arteriosus (PDA) is a
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1) (Five parts 23 marks in total) Persistent patent ductus arteriosus (PDA) is a medical condition that affects many very low-birth weight infants. Infants with PDA have an increased risk of serious ailment such as severe heart failure. The Apgar score is used to assess the health of an infant one minute after birth. The one-minute Apgar score measures how well the newborn tolerated the birthing process. A score of seven to 10 is normal and indicates the newborn is in good condition. Any score less than seven indicates that the baby needs assistance such as helping the infant breathe. Airway pressure is a measure of respiratory status, usually measured seven days after birth. Some researchers determined that early ibuprofen administration might prevent PDA in preterm neonates. A sample of 130 such infants was randomly divided into 4 groups. 32 were treated with one dose of ibuprofen, 33 with two doses, 33 with three doses, and 32 with a saline solution. The following is the description of variables under study Variable Gender Dose Weight Description of Variables Male OR Female Dose of ibuprofen (an integer from 0 to 3) Birth weight (in pounds) Gestational age (in weeks) One-minute Apgar score Air-way pressure (in cm H20) seven days after birth Score Pressure Statistics 252-Homework # 4 Questions-Fall 2017 For parts (a) - (d): (No output is required for these parts) Consider the regression model below (which will be referred to as the "original model"), where average air-way pressure seven days after birth is the response variable and the explanatory variables are weight, gender, and dose (where gender and dose are treated as categorical variables and weight is a numerical variable) (pressure weight ,GENDER, DOSE-A, + Aweight + .male + 3D1 + 4D2 + .D3 + 6(weight × male) +weight × D1) +weight × D2) + 9(weight × D3) + 10(weight × male × D1) + 11(weight × malex D2) + 12(weight × ma lex D3)Explanation / Answer
The effect of weight of infant on the airway pressure is present as an independent effect and also as a combined effect along with gender and dose of ibupfren.
So if we account for gener and dose that is take the average over gender and dose then the extra effect provided by Weight alone is beta_1, i.e. fo unit increase in weight, and taking the average over all other factors, the airway pressure increases by beta_1 amount.
However weight also has cross effects with gender and ose. So in the following chart we keep various combination of gender and dose and by putting the respective binary values('0' and '1') in the regression equation we find out the value of weight coeffecient which will be the impact of unit increase in weight on the airway pressure.
Male
Gender Dosage Effect of WeightMale
0 beta_1 + beta_6 Male 1 beta_1 + beta_6 + beta_7 + beta_10 Male 2 beta_1 + beta_6 + beta_8 + beta_11 Male 3 beta_1 + beta_6 + beta_9 + beta_12 Female 0 beta_1 Female 1 beta_1 + beta_7 Female 2 beta_1 + beta_8 Female 3 beta_1 + beta_9Related Questions
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