The available paths and their durations are: Path 1,5,7,8,12,15 with duration: 20 + 30 + 15 + 13 + 20 + = 98 days Path 1,5,7,8,12,14,15 with duration: 20 + 30 + 15 + 13 + 20 + 16 + = 114 days Path 1,6,8,12,15 with duration: 20 + 7 + 13 + 20 + = 60 days Path 1,6,8,12,14,15 with duration: 20 + 7 + 13 + 20 + 16 + = 76 days Path 2,9,14,15 with duration: 30 + 26 + 16 + = 72 days Path 3,10,15 with duration: 73 + 35 + = 108 days Path 4,11,13 with duration: 26 + 60 + 22 = 108 days ∑σ 2 = 4 + 25 + 1 + 9 + 9 + 1 + = 49 Z = (112 – 114)/7 = – 2/7 = – 0.285. 86