# Question

Samples of n = 4 items are taken from a process at regular intervals. A normally distributed quality characteristic is measured and x and s values are calculated for each sample. After 50 subgroups have been analyzed, we have

(a) Compute the control limit for the x and s control charts

(b) Assume that all points on both charts plot within the control limits. What are the natural tolerance limits of the process?

(c) If the specification limits are 19 4.0, what are your conclusions regarding the ability of the process to produce items conforming to specifications?

(d) Assuming that if an item exceeds the upper specification limit it can be reworked, and if it is below the lower specification limit it must be scrapped, what percent scrap and rework is the process now producing?

(e) If the process were centered at µ = 19.0, what would be the effect on percent scrap and rework?

(a) Compute the control limit for the x and s control charts

(b) Assume that all points on both charts plot within the control limits. What are the natural tolerance limits of the process?

(c) If the specification limits are 19 4.0, what are your conclusions regarding the ability of the process to produce items conforming to specifications?

(d) Assuming that if an item exceeds the upper specification limit it can be reworked, and if it is below the lower specification limit it must be scrapped, what percent scrap and rework is the process now producing?

(e) If the process were centered at µ = 19.0, what would be the effect on percent scrap and rework?

## Answer to relevant Questions

A company manufacturing oil seals wants to establish control charts on the process. There are 25 preliminary samples of size 5 on the internal diameter of the seal. The summary data (in mm) are as follows: and x R (a) Find ...Consider the x and R chart that you established in Exercise 6.15 for the piston ring process. Suppose that you want to continue control charting piston ring diameter using n = 3. What limits would be used on the x and R ...An x chart is used to control the mean of a normally distributed quality characteristic. It is known that σ = 6.0 and n = 4. The center line = 200, UCL = 209, and LCL = 191. If the process mean shifts to 188, find the ...Control charts for x and R are to be established to control the tensile strength of a metal part. Assume that tensile strength is normally distributed. Thirty samples of size n= 6 parts are collected over a period of time ...Control charts for and s are maintained on a quality characteristic. The sample size is n = 4. After 30 samples, we obtain (a) Find the three-sigma limits for the s chart. (b) Assuming that both charts exhibit control, ...Post your question

0