Below are some extracts from a paper describing a cross sectional study of 592 mothers and their new-born children investigating the association between cooking fuel (exposure) and birth weight (outcome) in Ghana. The exposure variable was coded O for "quid petroleum gas (LPG) use only and coded I for charcoal use only. The outcome (birth weight) was measured in grams. The authors also looked at garbage burning but you Will not consider this exposure here. Cooking fuel choices and burning practices as determinants birth weight: a cross-sectional study in Accra. Ghana What type of regression model would the authors have used? Justify you answer? (I mark) b) Look at the adjusted results for 'Term births' in Table 3, below. Interpret the coefficient (p) for 'charcoal use only', including its 95% confidence interval. (3 marks) Table 3 Adjuged of Cmki9 Fuel Use dBs stan'S Of Of LPG c) The authors then created a new categorical variable for charcoal use with categories 'low', 'moderate' and 'high'. Explain how they would have conducted a test for trend in R for this new variable and obtained a p-value. (3 marks)l d) Name three assumptions for this type of regression model and how you would test whether each one is met or not? (3 marks)