3. An agronomist fits a simple linear regression model for crop yield, measured in tons of wheat, and fertilizer, measured in hundreds of pounds. The data set contains 26 observations and produces the following results: Y = 50 + 4 X Se = 1.25 X bar = 210 (X - X bar)2 = 2500 a. What is the independent variable? ________________ (2 pts) b. What is the dependent variable? _________________ (2 pts) c. Interpret the estimated value of the true population slope coefficient? d. Suppose we wish to test whether or not there is a positive relationship between these two variables. What hypotheses would you use? (4 pts) HO: HA: e. What sampling distribution would apply to the test in part d? f. What is the CRITICAL value if alpha = 0.01? (3 pts) g. What is the CALCULATED value to compare to your answer in part (f) h. What would be the value of the measure of dispersion used to build a confidence interval for a mean value of Y when the independent variable equals 210? (5 pts)