This preview shows pages 1–3. Sign up to view the full content.
6. A medical facility does MRIs for sports injuries. Occasionally a test yields inconclusive
results and must be repeated. Using the following sample data and
n
= 200, determine the
upper and lower control limits for the fraction of retests using twosigma limits. Is the
process in control?
n = 200
Control Limits =
Thus, UCL is .0234 and LCL becomes 0.
Since n = 200, the fraction represented by each data point is half the
amount shown. E.g., 1 defective = .005, 2 defectives = .01, etc.
Sample 10 is too large. Omitting that value and recomputing limits with
UCL = .0197 and LCL = 0.
7. The postmaster of a small western town receives a certain number of complaints each day
about mail delivery. Determine threesigma control limits using the following data. Is the
process in control?
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document Control limits:
UCL is 16.266, LCL becomes 0.
All values are within the limits.
3. Checkout time at a supermarket is monitored using a mean and a range chart. Six
samples of
n
= 20 observations have been obtained and the sample means and ranges
This is the end of the preview. Sign up
to
access the rest of the document.
This note was uploaded on 01/04/2010 for the course OPM 311 taught by Professor Rui during the Spring '08 term at Binghamton University.
 Spring '08
 Rui

Click to edit the document details