Question

4. (5 Points) Control charts are to be kept on the thickness measurements for the process that produces steel tubing. The current specifications on the tubing are 0.1340 +0.0010 inch. After collecting 25 rational samples of size n 4 measurements at approxi half-hour intervals, the data were used to determine the sum of sample averages as 4.014 inches and the sum of sample ranges as 0.027 inch. Using X-bar and R control charts the process was declared in-control. Assume that the quality characteristic is normally distributed. Construct a 95% confidence interval for estimating the potential capability (Cp) for this process.

Answer 1

Sols Mea of OP the Sompe mean 25 냐.oly 25 2S - O. 6056 Mean of the Sampe barge. 25 25 o.oolo8 = o. 16056 t 0.729 XO.Dolo8 0163 Certl lie cL - * - o. 16056 D. 16056-lo.7 29χ0.00los)

R-cont sal chood n:4, D4 2.282 P3-o Uppen cont ool Lamrt 2.282x o.oolos Central kmit R ะ 0.00108 Louo corhol límit= oxo.oo108 Here psoed