Control charts are the most quantitative , problem solving quality improvement
tool
Walter Shewhart
Fives sources of variation
1. Environment
2. People/human/operator
3. Material
4. Equipment
5. Measurement
Types of variation
1. Piece to piece
2. Time to
Statistics denition:
1. Collection of data that pertains to an individual or groups of individuals,
people's, nations, things, etc.
2. science of statistics: tells us how to collect that data, tabulate, organize,
analyze, and present data
A. Descriptive(
Quality:
Joseph Juran: t for use (safety)
Phillip Crosby: zero defects
W. Edward Deming: meets & exceeds customer expectations at a price the
customer can afford in the proper conditions
developed the whole concept of SQC
80% on management
20% on labor
1. Check list (sheet)-list of things to do
2. Flow chart (diagram)-steps involved in performing a task
3. Fish bone diagram (Ishikawa/cause&effect)-helps identify the root cause of a
problem
4. Pareto chart (analysis)-
A. 20%pop has 80% of $
B. 80%pop ha
1. Defectives (non-conforming)
A. P-chart (proportion or fraction defectives)
B. 100 P-chart (percent defectives)
C. nP-chart (count of number of defectives)
2. Defects (non-conformities)
A. C-chart (average number of defects per unit) n=1
B. U-chart (ave
1. Probability of Rejecting a good lot: producers risk
2. Probability of Accepting a bad lot: consumers risk
1. Single sampling plans: taking one sample from the lot
A. n= sample size
B. Ac, C= acceptance number
2. Double sampling plans: two samples, on
Discrete Probability Distributions (whole numbers)
1. Hyper geometric probability distribution: sample from a nite lot P(d)=
A. N = pop
B. n = sample size
C. D = subset of interest
D. d = discrete event
2. Binomial Probability Distribution: innite (stead