Chapter 9

Question 1

What is Quality Control?

Answer 1

Quality Control is a process that evaluates output relative to a standard, and takes corrective action when output does not meet standards.

Purpose of quality control: assure that processes are performing in an acceptable manner.

Question 2

Inspection..

Answer 2

Make sure….
-Inputs are acceptable (acceptance sampling)(Input)

• Conversion of inputs into outputs proceeds in acceptable manner. (Process control)(Transformation)
• Finished goods conform to standards before being passed on to customers. (Acceptance sampling) (Output)

Question 3

Where to inspect the process for manufacturing and services?

Answer 3

Manufacturing-

• Raw Materials and purchased parts
• Finished Products
• Before a costly operation
• Before an irreversible process
• Before a covering Process

Services-

• Incoming purchased materials and supplies
• Personnel
• Service interfaces
• Outgoing completed work

Question 4

Statistical Process Control

Answer 4

Statistical evaluation of the output of a process during production.
It is based on repeated samples from a process.

Quality of conformance: Products/service conforms to specifications.

1) Take samples from process
2) Compare “statistically” to predetermined standard.

Question 5

What is a control chart and what does it do?

Answer 5

The essence of statistical process control is to assure that the output of the process is random so that future output will be random. Uses Upper Control limit(UCL), Center Line, and Lower Control Limit (LCL).

Purpose: to monitor process output to see if it is random (“in control”)

Question 6

What are the control limits in a Control Chart?

Answer 6

above and below center line at +-z standard deviations to define range of acceptable variation

Question 7

What are SPC Errors?

Answer 7

Type 1 error: concluding a process is “not in control” when it actually is

Question 8

Variables vs. Attributes

Answer 8

Variables- Data are measured, usually on continuous scale. ex length, width or weight of a part, amount of time needed to complete a task.

Attribute- data are counted. ex the number of defective parts in a sample, the number of calls per day.

Question 9

Read Chapter 9 Slides again

Answer 9

This chapter is huge