Quality Quiz 4

Seven Basic Quality Tools

cause and effect diagrams flowcharts checksheets pareto diagrams histograms control charts scatter diagrams

cause and effect diagram

(also called Ishikawa or fishbone diagrams): Identifies many possible causes for an effect or problem and sorts ideas into useful categories. Finding Problem

Types of Control Charts

1. Variables: a. Mean (x bar) charts: detects mean shifts or b. Range (R): detects spread changes 2. Attributes: a. p-Charts: proportion or b. c-Charts: avg. # of defects

normal distribution

68.26% of data falls within one standard dev, 95.46% within 2 standard devs, 99.73% within 3 standard devs

Pareto Chart

A bar graph that shows which factors are more significant.

Check Sheet

A structured, prepared form for collecting and analyzing data; a generic tool that can be adapted for a wide variety of purposes. Cataloging data

Flowchart

A technique that separates data gathered from a variety of sources so that patterns can be seen (some lists replace "stratification" with "flowchart" or "run chart"). Step by step

Control Chart

Graph used to study how a process changes over time. Comparing current data to historical control limits leads to conclusions about whether the process variation is consistent (in control) or is unpredictable (out of control, affected by special causes of variation). If process is in control (within control limits)

Scatter Diagram

Graphs pairs of numerical data, one variable on each axis, to look for a relationship. Find correlation

2 Components of Variation

Random Variation: common cause or background noise Assignable Variation: Special cause variation (

Histogram

The most commonly used graph for showing frequency distributions, or how often each different value in a set of data occurs. Shows patterns

Variability in TQM

Variability is either random or caused by production workers, that results in differences between different units of the final product. TQM identifies which variations can be solved and examines them in an attempt to eliminate them from the production process. TQM does this by introducing controls to the process, which could be more training, more inspections, higher quality standards, etc...

Value Stream Mapping (VSM)

a process that helps managers understand how to add value in the flow of material and information through the entire production process Delays that hold up the process restraints that limit the process excessive inventory

z score formula

z=(x-mean)/standard deviation then use chart to determine the probability If z score is negative: 1-probability if looking for % less than x: Just probability if looking for % greater than x: 1-probability