Question 19 2 pts Imagine a given predicting variable appears in both a conditional model and a marginal model (both models have the same response variable). The corresponding estimated regression coefcients for the predicting variable 0 can be ditTerent, not only in magnitude but also in sign. 0 must be the same. 0 can be ditTerent in magnitude but must have same sign. 0 must have the same magnitude, but not the same sign Question 20 2 pts The total number otunique pairwise comparisons among 5 group means is 010 0 120 024 0 None of the above Question 21 2 pts A dataset on sports related concussions contains 303 data points and three sports. Group A is a football, Group B rugby, and Group C is hockey. What are the degrees of freedom of the Fleet when comparing treatments (without intercept) using ANOVA? O F (2,300) O F (3,303) 0 F (2,302) 0 F (3,301) Question 22 2 pts In multiple linear regression, the error terms are assumed to 0 be dependent, and normally distributed With zero mean and constant Variance. 0 be independent, and normally distributed With zero mean and constant Variance. 0 be independent. and normally distributed With positive mean and constant Variance. 0 be dependent, and normally distributed With negative mean and constant variance. Question 23 2 pts Which one of the following is NOT an objective of Regression Analysis? 0 Prediction 0 Modeling 0 Testing Hypothesis 0 Extrapolation