please see below 1'q1 please answer all

Table 1.1 contains a portion of the data for a study of the relation of amount of body fat (Y) to scveral possible predictor variables, based on 20 healthy females 25 to 34 years old. The possible predictor variables are triceps skinfold thickness (X1), thigh circumference (X2), and midarm circumference (X3). The amount of body fat in Table 1.1 for each of the 20 persons was obtained by a cumbersome and expensive procedure requiring the immersion of the person in water. It would therefore be very helpful if a regression model with some or all of these predictor variables could provide reliable estimates of the amount of body fat since the measurements needed for the predictor variables are easy to obtain. Table 1.1: Body Fat Example X2:Y=19.174+0.222X1+0.659X2 - Regression of Y on X1 and X2:Y^=19.174+0.222X1+0.659X2 - Regression of Y on X1,X2 and X3:Y^=117.084+4.334X12.857X22.186X3. (1.1) Does adding X2 as a predictor variable to a model with only X1 as a predictor variable have a significant effect on the response variable Y ? Show all the assessment steps. (8) (1.2) Does adding X3 as a predictor variable to a model with X1 and X2 as predictor variables have a significant effect on the response variable Y ? Show all the assessment steps. (8) The following table gives fitted values (Yi), residuals (ei), leverages (hii) Cook's distances (Di) using the two predictor variables X1 and X2. (1.3) List all the influential observations according to the leverages. Show all the assessment steps. (1.4) List all the influential observations according to Cook's distances. Show all the assessment steps. (4)