Question Completion Status: QUESTION 16 The following information relates to Questions 16 and 17: Using a dataset including the baby's birth weight together with various characteristics of the mother, a researcher wishes to estimate the effect of smoking during the pregnancy on baby's birth weight. Here is the list of variables in the dataset. Variable 1 2 birthweight smoker 3 4 5 age educ unmarried Description Birthweight and Sreking Birth weight of infant (in grams) Indicator equal to one of the mother smoked during pregnancy and zero, otherwise Mother's Attributes age years of education attainment (more than 16 years coded as 17) indicator = 1 if mother is unmarried This Pregnancy indicator = 1 if mother drank alcohol during pregnancy number of drinks per week indicator = 1 if 1st prenatal care visit in 1st trimester indicator = 1 if 1st prenatal care visit in 2nd trimester indicator = 1 if 1st prenatal care visit in 3rd trimester indicator = 1 if no prenatal visits total number of prenatal visits 6 7 8 9 alcohol drinks tripre 1 tripre2 tripre3 tripreo nprevist 10 11 12 Save As Click Save and Submit to save and submit. Click Save All Answers to save all answers, Question Completion Status: 12 nprevist total number of prenatal visits When the researcher regressed birthweight on a constant and smoker, she obtained the Stata outcome as follows - let's call it Regression 1: regress birthweight smoker, robust Linear regression Number of obs F(1, 2998) Prob > F R-squared Root MSE = 3,000 89.21 0.0000 0.0286 583.73 = birthweight Robust Std. Err. Coef. t P>It [95% Conf. Intervall 0.000 smoker _cons -253.2284 3432.06 26.81039 11.89053 -9.45 288.64 -305.797 3408.746 -200.6597 3455.374 0.000 Click Save and Submit to save and submit. Click Save All Answers to save all answers. Arne Type here to search Bi Question Completion Status: When the researcher regressed birthweight on a constant, smoker, alcohol, and nprevist, she obtained the Stata outcome as follows - let's call it Regression 2: regress birthweight smoker alcohol nprevist, robust Linear regression h Number of obs F(3, 2996) Prob > F R-squared Root MSE 3,000 59.48 0.0000 0.0729 570.47 = Robust Std. Err. birthweight Coef. t P>t! (95% Conf. Intervall smoker alcohol -217.5801 -30.49129 26.10764 72.59671 -8.33 -0.42 0.000 0.675 -268.7708 -172.8357 -166.3894 111.8531 Click Save and Submit to save and submit. Click Save All Answers to save all answers, Show Timer Question Completion Status: birthweight Coef. Std. Err. t P>It! (95% Conf. Intervall smoker alcohol nprevist cons -217.5801 -30.49129 34.06991 3051.249 26.10764 72.59671 3.608326 43.7145 -8.33 -0.42 9.44 69.80 0.000 0.675 6.000 6.000 -268.7708 -172.8357 26.99487 2965.535 -166.3894 111.8531 41.14496 3136.962 Answer the following questions. In the response box, please label your answers clearly as a), b) and c). a) List two conditions for omitted variable bias (1 mark), and explain why the exclusion of alcohol and nprevist could lead to omitted variable bias in Regression 1 2 marks) b) Explain whether or not Regression 1 has omitted variable bias (2 marks). c) An alternative way to control for prenatal visits in Regression 2 is to use the binary variables tripreo through tripre3 The researcher tried to regress birthweight on smoker, alcohol, tripreo, tripre1, tripre and tripre3 But, she found that Stata automatically drops tripre. Explain why State does so (1 mark) Anal 3 (12pt) Chal Save and submit to save and submit. Click Save All Answers to save all answers, Question Completion Status: QUESTION 16 The following information relates to Questions 16 and 17: Using a dataset including the baby's birth weight together with various characteristics of the mother, a researcher wishes to estimate the effect of smoking during the pregnancy on baby's birth weight. Here is the list of variables in the dataset. Variable 1 2 birthweight smoker 3 4 5 age educ unmarried Description Birthweight and Sreking Birth weight of infant (in grams) Indicator equal to one of the mother smoked during pregnancy and zero, otherwise Mother's Attributes age years of education attainment (more than 16 years coded as 17) indicator = 1 if mother is unmarried This Pregnancy indicator = 1 if mother drank alcohol during pregnancy number of drinks per week indicator = 1 if 1st prenatal care visit in 1st trimester indicator = 1 if 1st prenatal care visit in 2nd trimester indicator = 1 if 1st prenatal care visit in 3rd trimester indicator = 1 if no prenatal visits total number of prenatal visits 6 7 8 9 alcohol drinks tripre 1 tripre2 tripre3 tripreo nprevist 10 11 12 Save As Click Save and Submit to save and submit. Click Save All Answers to save all answers, Question Completion Status: 12 nprevist total number of prenatal visits When the researcher regressed birthweight on a constant and smoker, she obtained the Stata outcome as follows - let's call it Regression 1: regress birthweight smoker, robust Linear regression Number of obs F(1, 2998) Prob > F R-squared Root MSE = 3,000 89.21 0.0000 0.0286 583.73 = birthweight Robust Std. Err. Coef. t P>It [95% Conf. Intervall 0.000 smoker _cons -253.2284 3432.06 26.81039 11.89053 -9.45 288.64 -305.797 3408.746 -200.6597 3455.374 0.000 Click Save and Submit to save and submit. Click Save All Answers to save all answers. Arne Type here to search Bi Question Completion Status: When the researcher regressed birthweight on a constant, smoker, alcohol, and nprevist, she obtained the Stata outcome as follows - let's call it Regression 2: regress birthweight smoker alcohol nprevist, robust Linear regression h Number of obs F(3, 2996) Prob > F R-squared Root MSE 3,000 59.48 0.0000 0.0729 570.47 = Robust Std. Err. birthweight Coef. t P>t! (95% Conf. Intervall smoker alcohol -217.5801 -30.49129 26.10764 72.59671 -8.33 -0.42 0.000 0.675 -268.7708 -172.8357 -166.3894 111.8531 Click Save and Submit to save and submit. Click Save All Answers to save all answers, Show Timer Question Completion Status: birthweight Coef. Std. Err. t P>It! (95% Conf. Intervall smoker alcohol nprevist cons -217.5801 -30.49129 34.06991 3051.249 26.10764 72.59671 3.608326 43.7145 -8.33 -0.42 9.44 69.80 0.000 0.675 6.000 6.000 -268.7708 -172.8357 26.99487 2965.535 -166.3894 111.8531 41.14496 3136.962 Answer the following questions. In the response box, please label your answers clearly as a), b) and c). a) List two conditions for omitted variable bias (1 mark), and explain why the exclusion of alcohol and nprevist could lead to omitted variable bias in Regression 1 2 marks) b) Explain whether or not Regression 1 has omitted variable bias (2 marks). c) An alternative way to control for prenatal visits in Regression 2 is to use the binary variables tripreo through tripre3 The researcher tried to regress birthweight on smoker, alcohol, tripreo, tripre1, tripre and tripre3 But, she found that Stata automatically drops tripre. Explain why State does so (1 mark) Anal 3 (12pt) Chal Save and submit to save and submit. Click Save All Answers to save all answers