SPC Simplified

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What is the main goal of Statistical Process Control (SPC)?

To increase process variation

To create a detailed flowchart

To stabilize the process and meet customer requirements (correct)

To focus on recognizing improvements

What is the purpose of using small Post-it® notes on a flowchart?

To make the process less changeable

To limit the number of decisions and activities

To demonstrate process improvements

To increase clarity and ease of change (correct)

When can improvement efforts begin in a process?

Before stabilizing the process

After stabilizing and making the process predictable (correct)

Before meeting customer requirements

After implementing the process indicators

What is the significance of control charts and histograms in a process?

To demonstrate improvements in the process Signup and view all the answers

How should detailed sub-processes be managed in a flowchart?

Move them to additional pages Signup and view all the answers

Where should every person or department involved in delivering the product or service be listed on a flowchart?

Across the top of the flowchart Signup and view all the answers

What are the two outcomes for any improvement effort?

Center the distribution over the target value and reduce the spread of the distribution. Signup and view all the answers

How do customers specify their requirements for targets and tolerances?

Target and a bilateral tolerance Signup and view all the answers

What are specification limits used to determine?

Goal posts and process capability Signup and view all the answers

How are control limits in control charts different from specification limits?

Control limits are based on customer expectations, while specification limits focus on process capability. Signup and view all the answers

What are the three key characteristics of distributions mentioned in the text?

Center, spread, and shape Signup and view all the answers

How can you monitor the outcomes of improvement efforts according to the text?

By analyzing histograms Signup and view all the answers

What does a shape parameter of less than 1 in failure rate describe?

Decreasing failure rate (infant mortality) Signup and view all the answers

What does a shape parameter of 3.6 in failure rate approximate?

Normal distribution Signup and view all the answers

What does the scale parameter (characteristic life) signify?

Age at which 63.2% of units will have failed Signup and view all the answers

How can one determine when a certain percent of parts will have failed using Weibull Probability Plot?

Using specification limits Signup and view all the answers

In the given example, what percentage of parts will have failed by time 27?

10% Signup and view all the answers

How can one calculate the actual defect rate in parts per million (PPM)?

Using the standard deviation and specification limits Signup and view all the answers

What does the Cpk measure in statistical process control?

If data fits between the upper and lower specification limits Signup and view all the answers

If Cp is less than Cpk, what does it indicate?

Data is centered but does not fit between the spec limits Signup and view all the answers

What is the main difference between Pp and Ppk in statistical process control?

Pp uses an estimation of standard deviation, while Ppk uses the actual standard deviation of the data Signup and view all the answers

In statistical process control, what does Weibull analysis excel at?

Working well with failure rates and small samples Signup and view all the answers

What corrective action should be taken if Cp = Cpk and both are between 1.0 and 1.33?

Improve the process to reduce variation Signup and view all the answers

What type of data is Weibull analysis especially suited for?

Failure rates data (e.g., time until failure) Signup and view all the answers

What is the purpose of the XbarS chart?

To monitor and evaluate process performance using time, length, weight, or cost when there are 6–25 samples per period Signup and view all the answers

What should be done to view charts for each data set in the X Chart Formulas Data Input Sheet?

Click on the arrows Signup and view all the answers

When is the Xmr or c, p, u, np chart dashboard opened?

After entering data into the data input sheet Signup and view all the answers

What do the control chart dashboards in QI Macros contain?

An instruction sheet, a data input sheet, and a sheet for each available control chart and a run chart Signup and view all the answers

Which type of chart is used to monitor and evaluate process performance when there are more than 25 samples per period?

Range Chart Signup and view all the answers

What action should be taken to create a dashboard with each available control chart?

Click on the Create Dashboard icon Signup and view all the answers