The document calculates the Z-score corresponding to an 86% confidence level in 5 steps: 1) it finds that α is 0.14, 2) calculates α/2 as 0.07, 3) draws the standard normal distribution curve, 4) determines the area to the left is 0.93, and 5) uses tables to find that the Z-score closest to an area of 0.93 is 1.48.