A confidence interval for a population mean has a margin of error of 2.6. a. Determine the length of the confidence interval. b. If the sample mean is 51.7, obtain the confidence interval. c. Construct a graph that illustrates your results. Assume that the variable under consideration has a density curve. It is given that 26.8% of all possible observations of the variable are less than 17. a. Determine the area under the density curve that lies to the left of 17 b. Determine the area under the density curve that lies to the right of 17