Solve Questions 14, 15, 16 according to the following information: The ranges of five electric vehicles are measured before a software upgrade and then again after the software upgrade is applied: 14. (2 points) Compute the sample mean d of the differences (after - before). A. 50.3 B. 49.2 C. 45.8 D. 51.2 E. 47.6 15. (2 points) Compute the sample variation s2 of the differences. A. 67.3 B. 70.8 C. 36.4 D. 60.7 E. 28.2 16. ( 2 points) Form a 99% (two-sided) confidence interval for the mean difference with the data provided. A. 34.55