Instructions: the exam consists of six (6) questions. Answer all questions in the exam booklets provided. Be sure your name and student number are printed clearly on the front of all exam booklets used. Do not write answers to questions on the front page of the first exam booklet. Please label clearly each of your answers in the exam booklets with the appropriate number and letter. A table of percentage points of the t-distribution is given on the last page of the exam. The marks for each question are indicated in parentheses immediately above each question. All questions pertain to the simple (two-variable) linear regression model for which the population regression equation can be written in conventional notation as: 2 i i (1) where yi and xi are observable variables, 1 and 2 are unknown (constant) regression coefficients, and ui is an unobservable random error term. The ordinary least squares (ols) sample regression equation corresponding to regression equation (1) is.