A Producer of Specialty Products Uses a Variety of Natural

Essay

A producer of specialty products uses a variety of natural and man-made materials to make unique countertops for kitchens and baths. One product line mixes concrete and natural river stone to make countertops that are polished to a high shine revealing unique patterns. Occasionally coarse sand will result in undesirable pitting and rough spots on surfaces. Consequently, as part of its quality control efforts, 8 by 4 foot polished slabs are checked periodically for imperfections. For each slab inspected the number of imperfections (pits, rough spots, etc.) is recorded.
a. What type of control chart should be used for these data?
b. If the average number of imperfections per 8 by 4 foot polished slab is 2.6, calculate the centreline and control limits for the appropriate control chart.