Question 1: First you will discuss the study design and compare the FEV measurements of children of smoker parent(s) with that of nonsmoker parents.

(a) Comment about the study design. Is the study an example of an observational study or a randomized experiment? Can we use the study to assess the effect of second-hand smoking on FEV of children exposed to second-hand smoking at home? Provide brief explanations. List some potential confounding variables in the study.

SIMPLE LINEAR REGRESSION In simple linear regression model the mean of a response variable is a linear function of a single explanatory variable. The model and the associated inferences are valid as long as the assumptions of independence, normality and constant variance are not violated. In this assignment you will use a linear regression model to examine the relationship between the volume of air exhaled during a forced breath (an important measure of pulmonary function) and one of the following explanatory variables: age, height, sex, and parental smoking. In particular, the effect of parental smoking on the volume will be discussed. You will also compare the inferences based on the t-tools with those produced by simple linear regression model. Second-hand Smoking and Childhood Respiratory Disease Almost half of all Canadian children under the age of 15, some 2.8 million children, are exposed to second-hand smoke on a regular basis. The effect of second-hand smoking on the pulmonary function of children was studied by many researchers. Studies have shown that children (especially infants) of parents who smoke have more lung illnesses, such as bronchitis and pneumonia, and can develop asthma. Still 85% of adults who smoke and who live with a child do not ensure that the child is not exposed to the smoke from their cigarettes. One of the important measurements of lung function and effective tool to diagnose pulmonary disease is the volume of air expelled in the first second from the level of total lung capacity (FEV). It is expected that the volume may be lower for the children exposed to second-hand smoke at home. In order to verify the hypothesis, the FEV measurements were obtained for 654 subjects, age 6-22 who were seen in Childhood Respiratory Disease Clinic in Easton Boston, Massachusetts. This dataset is available in the Data link located in the Lab 3 tab display in the Labs section on eClass. The data are not to be printed in your submission. The following is the description of variables in the data file: Column Variable Description of Variables Age Age (in years), FEV Volume of air expelled in the first second (in liters), WAWN- Height Height (in inches), Sex Male or Female, Smoker Non = Nonsmoker parents, Cur = Current smoker parent(s)