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Problem 6. Regression model (student exam dataset) Based on the dataset "Student.cv", use the following dependent variable and independent variables to build a linear regression model. Dependent Variable: Y: Grade. Independent Variables: X1: gender X2: Announcement.View X3: Discussion. Times X4: Student.Absence.Days Call : Im(formula = Grade ~ gender + Announcements. View + Discussion. Times + Student . Absence . Days, data = oh) Residuals : Min 1Q Median 30 Max -19.878 -5.551 1.091 6.088 11.294 Coefficients: Estimate Std. Error t value Pr(>Itl) (Intercept) 88 . 581444 0. 909208 97.427 a) Write down your regression model with estimated coefficient. = 88.5814 - 1.0378x1 + 0.0397x2 + 0.0083x3 + 1.5574x4 b) Is the Discussion Time a significant factor for the Grade? Do a t-test (hypothesis test) on the slope at the significance level of 5%. Ho: B3 = 0 Ha: B3 # 0