Exam 19: Statistical Methods for Quality Control

In practice, it is common to use the sample _____ to estimate the process _________.

In acceptance sampling, the risk of accepting a poor quality lot is known as

To inspect incoming shipments of components, a manufacturer is considering samples of sizes 12, 15, and 18. Use binomial probabilities to select a sampling plan that provides a producer's risk of $\alpha$ = .12 when p₀ is .04 and a consumer's risk of $\beta$ = .08 when p₁ is .25.

__________ consist(s) of making a series of inspections and measurements to determine whether quality standards are being met.

Harry Coates wants to construct and R charts at the bag-filling operation for Meow Chow cat food. He knows that when the filling operation is functioning correctly, bags of cat food should average 50.00 pounds and 5-bag samples should have an average range of .330 pounds.Harry had twenty 5-bag samples taken at 2-hour intervals and the sample means and ranges are shown below. Determine the center lines and upper and lower control limits for the and R charts.

Every check cashed or deposited at Lincoln Bank must be encoded with the amount of the check before it can begin the Federal Reserve clearing process. The accuracy of the check encoding process is of utmost importance. If there is any discrepancy between the amount a check is made out for and the encoded amount, the check is defective.Twenty samples, each consisting of 250 checks, were selected and examined. The number of defective checks found in each sample is shown below. The manager of the check encoding department knows from past experience that when the encoding process is in control, an average of 1.6% of the encoded checks are defective. a. Determine the center line and the 3-sigma control limits for the p chart. b. Plot the twenty recent sample findings on the chart and decide if the check encoding operation is in control.

A process sampled 30 times with a sample of size nine resulted in = 12.7 and = 0.8. Compute the upper and lower control limits for the and charts for this process.

A soft drink filling machine is set up to fill bottles with 12 ounces of soft drink. The standard deviation s is known to be 0.4 ounces. The quality control department periodically selects samples of 16 bottles and measures their contents. Assume the distribution of filling volumes is normal. a.Determine the upper and lower control limits and explain what they indicate. b.The means of six samples were 11.8, 12.2, 11.9, 11.9, 12.1, and 11.8 ounces. Construct an x-bar chart and indicate whether or not the process is in control.

An acceptance sampling plan with n = 20 and c = 1 has been designed with a producer's risk of .12. a. Was the value of p₀ equal to .02, .03, .04, or .05? b. What is the consumer's risk associated with this plan if p₁ is .08? c. Assume the consumer's risk found in (b) is unacceptably high. Which modification of the sampling plan will result in the greater reduction of the consumer's risk, increasing n to 30 or decreasing c to 0?

The following data represent the filling weights based on samples of 14.5 ounce cans of whole peeled tomatoes. Ten samples of size 5 were taken. Use Excel to develop an R chart.

Control charts based on data that can be measured on a continuous scale are called

Process control and acceptance sampling procedures are most closely related to

The following data represent the filling weights based on samples of 350-gram containers. Ten samples of size 5 were taken. Use Excel to develop an R chart.

A process that is in control has a mean of $\mu$ = 56.5 and a standard deviation of $\sigma$ = 3.4. What should the control limits be for a sample mean chart if samples of size 8 are taken?

A production process is considered in control if 4% of the items produced are defective. Samples of size 100 are used for the inspection process. a.Determine the standard error of the proportion. b.Determine the upper and the lower control limits for the p chart.