17-6. The overall length of a cigar lighter body used in an application is controlled and R charts. The following table gives length for 20 sam ples of size 4 (measurements are coded from 5.00 mm; that is, 15 is 5.15 mm) (a) Set up the X and R charts. Is the process in statistical control? (b) Specifications are 5.10 t 0.05 mm. What can you say about process capability?