A textile company wants to assess the quality of the dyeing process used in the production of fabrics. It has been observed that occasionally a stronger small spot of paint appears on the fabric.
To check if the number of spots remains within a normal range, a statistical control process is implemented. Every quarter of an hour, the number of spots per piece of cloth is recorded.
The file named FABRIC.MTW contains the data of the fabrics produced in one day. Column C1 contains the number of spots per piece of fabric. Since the pieces of cloth are not exactly the same, in column C2 the surface area (in m2) per piece of cloth is also recorded.