PROMGT3 Quiz 2 Flashcards
These charts are applied to data that follow a continuous distribution (measurement data)
Variables Control Charts
These charts are applied to data that follow a discrete distribution
Attributes Control Charts
Types of Process Variability
Stationary behavior, uncorrelated data
Stationary behavior, autocorrelated data
Nonstationary behavior
_________________ are most effective when the in-control process data is stationary and uncorrelated
Shewhart control charts
________________ is a collection of tools that when used together can result in process stability and variability reduction
Statistical process control
Seven major tools are:
Histogram or Stem and Leaf Plot
Check Sheet
Pareto Chart
Cause and Effect Diagram
Defect Concentration Diagram
Scatter Diagram
Control Chart
A process that is operating with only ________________ present is said to be in statistical control.
Chance causes of variation
A process that is operating in the presence of ______________ is said to be out of control
Assignable causes
The eventual goal of SPC is ___________ or _________________ in the process by identification of assignable causes.
Reduction or Elimination of Variability
If ___________________________________ and __________________, the process is out of control
At least one point plots beyond the control limits
The points behave in a systematic or nonrandom manner.
Type I Error, denoted by ________, is the probability of ____________________.
Alpha; saying that the process is out of control when it is in control
Type II Error, denoted by ________, is the probability of ____________________.
Beta; saying that the process is in control when it is out of control.
Type I error follows that the null hypothesis is ___________ whereas Type II error follows that if the null hypothesis is ______________
Rejected if it is true
Accepted when it is false
The use of 3-sigma limits, also known as _________, is applicable when the distribution of the _________ characteristic is well approximated by the __________ distribution.
Action limits; quality; normal
Warning limits are typically set at _____________ from the mean
Two standard deviations
If one or more points fall between the warning limits and the control limits, or close to the warning limits, this indicates that ________________.
The process may not be operating properly
What are the good and bad things when using warning limits?
Good: Increases sensitivity of the control chart
Bad: Could result in an increased risk of false alarms.
________ samples make it easier to detect small shifts in the process
Larger
Average Run Length (ARL) is a very important way of determining the appropriate ___________ and _____________.
Sample size; sampling frequency