BUS310_L12_2.17.11 - Problem Set 2 Review • Lecture 12...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Problem Set 2, Review • Lecture 12 Chapter 14: Process Control Charts Special Cause of Variation (Outlier): A measurement this far from the process mean is very unlikely if only expected variation is present Process Mean UCL LCL +3σ- 3σ time Common Cause Variation: range of expected variability Special Cause of Variation (Outlier) Control chart shows if variation in data are due to: Common Cause Variation • Naturally occurring and expected fluctuations (normal variation in materials, tools, machines, operators, and the environment) • Reduced only by changing the process Special Cause Variation • Fluctuations or patterns not inherent to a process, often unusual events • Problems to be corrected or opportunities Data outside control limits or trends (Rules 1, 2, 3) Each dot corresponds to the sample statistic for a subgroup (one of the samples collected of the process output over time) Categorical variables (rooms ready or not) : sample proportion (rooms not ready) • P-Chart Numerical variables: range, mean (delivery times) • Range and Mean charts Process In Control • Process in control: points are randomly distributed around the center line and all points are within the control limits (only common cause variation) UCL LCL time Process Mean r This variation is normal for this process. • If variation is small enough for customer satisfaction, control chart is used to monitor the process • If the common-cause variation is too large, alter the process Process Out of Control: Rule 1 • One or more points outside control limits UCL LCL Process Mean Special Cause Variation: Outliers Special causes of variation must be identified • If detrimental to quality, remove • If increasing quality, incorporate into the process design Each dot corresponds to the sample statistic for a subgroup (one of the samples collected of the process output over time) Numerical variables: range, mean (delivery times) • Range and Mean charts r There was one sample of delivery times, whose mean was out of range Process Out of Control: Rule 2 § Eight or more points in a row on one side of the center line UCL LCL Process Mean Special Cause Variation: Pattern over Time Special causes of variation must be identified • If detrimental to quality, remove • If increasing quality, incorporate into the process design Each dot corresponds to the sample statistic for a subgroup (one of the samples collected of the process output over time) Numerical variables: range, mean (delivery times) • Range and Mean charts à 8 consecutive samples of delivery times are below the mean. à Why? (not a random variation in the process, potential opportunity) Process Out of Control: Rule 3 § Eight or more points moving in the same direction....
View Full Document

This note was uploaded on 04/07/2011 for the course BUS 311 taught by Professor Reardon,j during the Spring '08 term at University of Hawaii, Manoa.

Page1 / 61

BUS310_L12_2.17.11 - Problem Set 2 Review • Lecture 12...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online