Exam 18: Statistical Process Control

Repeated sampling of a certain process shows the average of all sample ranges to be 1.0 cm.The sample size has been constant at n = 5.What are the 3-sigma control limits for this R-chart?

A index greater than ________ is a capable process,one that generates fewer than 2.7 defects per 1000 at the ±3σ level.

Natural variations

A Type II error occurs when

A normal distribution is generally described by its two parameters: the mean and the range.

If the process average is in control,then the process range must also be in control.

When a lot has been accepted by acceptance sampling,we know that

A local manufacturer supplies you with parts,and you would like to install a quality monitoring system at his factory for these parts.Historically,the defect rate for these parts has been 1.25% (You've observed this from your acceptance sampling procedures,which you would like to discontinue).Develop ± 3σ control limits for this process.Assume the sample size will be 200 items.

If = 23 ounces,σ = 0.4 ounces,and n = 16,the ±3σ control limits will be

A manufacturer uses statistical process control to control the quality of the firm's products.Samples of 50 of Product A are taken,and a defective/acceptable decision is made on each unit sampled.For Product B,the number of flaws per unit is counted.What type(s)of control charts should be used?

A Cpk index of 1.00 equates to a defect rate of

Ten samples of size four were taken from a process,and their weights measured.The sample averages and sample ranges are in the following table.Construct and plot an x-bar and R-chart using this data.Is the process in control?

The ________ is the percent defective in an average lot of goods inspected through acceptance sampling.

A lot that is accepted by acceptance sampling is certified to be free of defects.

An acceptance sampling plan's ability to discriminate between low quality lots and high quality lots is described by

Acceptance sampling

Which of the following statements about acceptance sampling is true?

A woodworker is concerned about the quality of the finished appearance of her work.In sampling units of a split-willow hand-woven basket,she has found the following number of finish defects in ten units sampled: 4,0,3,1,2,0,1,2,0,2. a.Calculate the average number of defects per basket b.If 3-sigma control limits are used,calculate the lower control limit,centerline,and upper control limit.

What does it mean for a process to be "capable"?

Pierre's Motorized Pirogues and Mudboats is setting up an acceptance sampling plan for the special air cleaners he manufactures for his boats.His specifications,and the resulting plan,are shown on the POM for Windows output below.In relatively plain English (someone else will translate for Pierre),explain exactly what he will do when performing the acceptance sampling procedure,and what actions he might take based on the results.