Question

Question 3 A researcher is interested in the relationship between the birth weights of infants and mothers' smoking habits. He uses the birth weight of an infant (ounces) and the average number of cigarettes the mother smokes per day during the pregnancy as the dependent and independent variables, y and x, respectively. Using a sample of size (1388 the following model is obtained by the method of least squares: y-119.770.514.x (3.15) (0.13) SE e the figures in brackets are the standard errors for the parameter estimates (a) Does the given information support the conclusion that the two parameters in the regression are significantly different from zero? (4 marks) Infer the predicted birth weight for a non-smoking mother. And what is the predicted birth weight for a mother who takes 20 cigarettes per day on average? (4 marks) (b) Infer if this simple linear regression necessarily capture a causal relationship between the birth weight of an infant and the mother's smoking habits. Explain (c) (3 marks) (d) To predict a birth weight of 125 ounces, what value would the independent (4 marks) (e) The proportion of mothers in the sample who do not smoke while pregnant is (5 marks) ct an interval estimate for the slope parameter B, at a 0.05. Does this (5 marks) variable take? Is this sensible? Comment on it briefly. about 0.85. Interpret if this helps to reconcile your finding in part (c) result support your conclusion in part (a)?

Answer 1

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