Chapter 5 - Variable Control Charts Flashcards
Enhances the analysis of the process by showing how that process is performing over time
A Control Chart
Where no two items or services are exactly the same
Variation
Types of variation
Within-piece, piece-to-piece, and time-to-time
Small random changes in the process that cannot be avoided
Common causes
Variations in the process that can be identified as having a specific cause
Assignable Causes
The central tendency of the data
Centerline
Yeah measurable characteristics of a product
Variables
Calculated based on + or - 3 Sigma
Upper/Lower Control Limit
Used to monitor the variation of the subgroup averages that are calculated from the individual samples data.
X Bar Chart
Will have been produced under the same conditions, by the same machine, the same operator, the same mold, etc.
A Homogenous Subgroup
The grand average of the subgroups
Double X Bar
Calculated by summing the values of the individual ranges and dividing by the number of subgroups m
R Bar
Used to evaluate the variation in quality from subgroup to subgroup
X Bar Chart
A method of determining the amount of variation in the individual samples
Range Chart
When the performance of the process falls within statistically calculated control limits and exhibits only chance, or common, causes.
Under Control
