Use SAS to fit the 3 models. Write down the fitted models. For each model, determine the predicted cholesterol level for patient 4, and compare these predicted values with the observed value. Comment on your findings.For the model Y=, test whether at significance level 0.05. Specify your hypothesis, test statistics and its value, p-value and your conclusion.Construct the 95% CI for in the model Y=. What does this CI tell you about the existence of linearity relationship between Y and X1, controlling for X2?For the model Y=, test whether simultaneously at significance level 0.05. Specify your hypothesis, test statistics and its value, p-value and your conclusion.