Exam 15: Statistical Quality Control

Robert Pirsig defines quality as "Fitness for use."

Table 15-1 -Refer to Table 15-1.Bags of chocolate candy are sampled to ensure proper weight.The overall average for the samples is 36 ounces.Each sample contains twelve bags.The average range is 1.3 ounces.The upper control chart limit for the sample averages would be

Table 15-1 -Use the data shown below and the information in Table 15-1 to develop an upper control limit for a control chart that monitors central tendency.What is the upper control limit?

The area from two standard deviations above to two standard deviations below the mean of a normal distribution will contain 99.7% of all of the area under the curve.

Which of the following control charts is/are for variables?

Explain the difference between an x-bar chart and a R-chart.

A company has been receiving complaints about the attitude of some sales clerks.Over a 10-day period, the total number of complaints was 250.The company wishes to develop a control chart for the number of complaints.What would the lower control limit on the number of complaints per day be for a 2 sigma (95.5%)control chart?

The inspection of cans of juice involves sampling some cans and weighing them.The overall average for the samples is 39 ounces.Each sample contains 36 cans.The standard deviation is estimated to be 2 ounces.The 99.7% lower control chart limit for the average would be

R-charts measure changes in

The c-chart is useful when we

The -chart would be useful when we

Who introduced control charts in 1924?

charts indicate changes in

Table 15-1 -Refer to Table 15-1.Bags of chocolate candy are sampled to ensure proper weight.The overall average for the samples is 36 ounces.Each sample contains eight bags.The average range is 1.3 ounces.The lower control chart limit for the sample averages would be

A p-chart has been developed for a particular item.In the past, 4% of such items have been found to be defective.If a sample of 100 is taken, and 9 of these are found to be defective, should the process be considered out of control based on 95.5% control limits? Explain.

A p-chart is based on which of the following probability distributions?

Explain the difference between a p-chart and a c-chart.

A run of four consecutive points above the center line is a sufficient reason to stop the process and investigate for cause.

Table 15-1 -Refer to Table 15-1.To guarantee that cans of soda are properly filled, some cans are sampled and the amounts measured.The overall average for the samples is 12 ounces.Each sample contains 10 cans.The average range is 0.4 ounces.The lower control chart limit for the sample averages would be

A c-chart would be appropriate to monitor the number of weld defects on the steel plates of a ship's hull.