Exam 6: Statistical Quality Control

Inspectors want to develop process control charts to measure the weight of crates of wood. Data (in pounds)from three samples are: Sample Crate 1 Crate 2 Crate 3 Crate 4 1 18 38 22 26 2 26 30 28 20 3 26 26 26 26 (a)What is the upper control limit for the R chart? (b)What is the lower control limit for the R chart? (c)What is the upper control limit for the x-bar chart? (d)What is the lower control limit for the x-bar chart? (e)Is the process in a state of control? If not, why not?

Describe how finance is associated with SQC.

What are the three broad categories of statistical quality control?

Joel's fresh flower processing plant processes 2000 flowers in a lot. For quality control they use a sample size of 10 flowers. Joel has established a probability of accepting a given lot as 99.74% with a proportion of defective items, in a lot, of .05. What is the AOQ?

Acceptance sampling occurs after the product has been produced.

What are the two types of control charts for attributes?

Suppose a process has been monitored daily for the last ten days and the number of machine failures each day was noted. The results follow: Day Number: 1 2 3 4 5 6 7 8 9 10 Number of Failures: 8 9 6 10 12 4 9 11 9 12 Compute control limits for a c-chart that monitors the average number of machine failures per day. Is the process in a state of control?

For which of the following would a control chart for attributes not be appropriate?

According to the text, what percent of defects are consumers generally willing to accept?

What is the formula for an R chart's center line?

Upper and lower control limits are usually set at  6 standard deviations from the mean.

Suppose that you want to measure the percentage of candles that are cut longer than 9 inches. Which control chart would be appropriate?

What is the formula for the sample standard deviation of a variable measured as a fraction or probability?

A control chart y-axis represents the quality characteristic that is being monitored.

The standard deviation is an example of what?

What is the upper control limit for a c-chart if the total defects found over 20 samples equals 150?

Julia has been assigned to develop a new product design specifications. Manufacturing has stated that the system must have a capability index of 1.2 when the product standard deviation is 1.3. What is the specification range limits?

Ritz-Carlton employees are empowered to spend up to how much money on the spot to correct any customer complaint?

A process chart is a

Define attribute (as a product characteristic).