Suppose X, is a numerical variable and X, is a dummy variable with two categories and the regression equation for a sample of n=26 is =4-3X-2X2- a. Interpret the regression coefficient associated with variable X. b. Interpret the regression coefficient associated with variable X2. c. Suppose that the tSTAT test statistic for testing the contribution of variable X, is -2.91. At the 0.10 level of significance, is there evidence that variable X2 makes a significant contribution to the model? Holding constant the effect of a positive change of unit(s). for each increase of one unit in the predicted mean value of Y by b. Interpret the regression coefficient associated with variable X2 Holding constant the value of changing the value of mean value of Y by a positive change of unit(s). from to is estimated to the predicted c. Determine the null and alternative hypotheses. Ho H State the test statistic. LCTAT (Round to two decimal places as needed.)