18. Construct a PTPC chart for the data in Exercise 4. Use the average value for Part 1 and Part 2 . For example, the data for 0800 h would be Part 1 (59.993 + 60.010)>2

= 60.0015 and Part 2 (59.998 + 60.013)>2 = 60.0055.

Do not use Part 3 .