Applied Statistics
for Industry I
STAT 495
Fall 2010
1
Goals and Objectives
Understand Statistical
Thinking
Appreciate Variability
Apply Methods
2
Instructor
W. Robert Stephenson
 phone: (515) 294-7805
 fax:
(515) 294-4040
 email: wrstephe@iastate.edu
 homepage:
www.public.iastate.edu/~wrstephe
3
Office Hours
T Th
9:00- 9:50 Central
MWF 11:10-11:50 Central
and by appointment (give me
a call or send an email to set
up a time)
4
Required Materials
Statistical Quality Design and
Control, 2nd Edition, by DeVor,
Chang and Sutherland.
 Lecture notes on WebCT.
 Handouts on WebCT or course
Web site.
5
Computing
JMP version 8
 Available
for free for students at
Iowa State University
www.sitelicensed.iastate.edu/software/
 You
can use other software but
I may not be able to help you if
you have problems.
6
Exams
Exam 1: September 28
Exam 2: November 2
Final Exam: December 14,
9:45 am to 11:45 am
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Schedule and Due Dates
 This is a synchronous course,
which means off campus students
can view it in real time.
 You can also view the lectures
whenever you want.
 Please contact me should work
assignments interfere with the
schedule or due dates.
8
Assignments
Reading
 Before viewing tapes (if possible)
Homework
 Due date specified (usually one
week after it is assigned)
 Returned within a week (solutions
will be posted on WebCT)
9
Grading
Exam 1 :
Exam 2 :
Final Exam :
Homework:
Project:
Total :
100 pts
100 pts
130 pts
100 pts
70 pts
500 pts
10
Team (Individual) Project
 On Campus - Teams of 3 or 4.
 Off Campus – If there are several
students at your company, a team
project is preferred. However,
students can work individually.
 Use the ideas and methods
presented in this course on a
process.
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Team (Individual) Project
The process may be one at
work (provided it is not
proprietary) or one of
personal interest.
A final report will be due prior
to the date of the final exam.
12
The Big Picture
A Case Study for a
Metal Alloy Process
13
Outline
Problem
Process
 Atmosphere
 Settings
Shewhart’s Concept of a
Process
14
Outline (cont.)
Deming’s Responsibility
Assignment
Process Capability
Process Improvement
15
The Problem
A manufacturer of metal alloy
parts was not meeting customers’ requirements for :
strength
density
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The Process
Weigh
Powders
Mix
Powders
Fill
Mold
Press
to
Shape
Test
Machine
Sinter
17
Atmosphere
Development on a small
scale
Problems with full scale
production
Manufacturing blames R&D
R&D blames manufacturing
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Process Settings
Rate of Temperature Rise
200 C/hr
Maximum Temperature
 1400 C
Time at Maximum Temperature
 2 hr

19
Quality Characteristics
Density
Target: 16.0 gms/cc
Elongation
 Minimum: 18%

20
Shewhart’s Concept of a
Process
Materials
Methods
Machines
People
21
Shewhart’s Concept of a
Process (Cont.)
Measurement
System
Output
22
Variability
Attributable to assignable
causes
Attributable to chance or
common causes
23
Variables Control Chart
R of Density
3.0
UCL=2.784
Range of Density
2.5
2.0
1.5
Avg=1.220
1.0
0.5
0.0
LCL=0.000
-0.5
0
5
10
15
20
Sample
25
30
35
24
Variables Control Chart
XBar of Density
19.0
Mean of Density
18.0
17.0
UCL=16.594
16.0
Avg=15.705
15.0
LCL=14.816
14.0
13.0
0
5
10
15
20
Sample
25
30
35
Note: The sigma was calculated using the range.
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Control Charts for Density
Range: no out of control
signals but substantial
variation.
X-bar: several points outside
the control limits.
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Deming’s Responsibility
Assignments
Statistical Control?
Yes
Good
Results?
Yes
No
No
No
Action
Manage- Local
Work
ment
Force
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Variables Control Chart
R of Density (After)
Range of Density (After)
3.0
UCL=2.647
2.5
2.0
1.5
Avg=1.160
1.0
0.5
0.0
LCL=0.000
-0.5
0
5
10
15
Sample
20
25
28
Variables Control Chart
XBar of Density (After)
Mean of Density (After)
17.0
UCL=16.722
16.5
16.0
Avg=15.877
15.5
LCL=15.032
15.0
0
5
10
15
Sample
20
25
Note: The sigma was calculated using the range.
29
Control Charts for Density
Range: no out of control
signals but still substantial
variation.
X-bar: no points outside the
control limits.
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Process Capability
Is the process capable?
graphical procedure
 capability indices

31
32
Capability
Spec Limits
Column
Density (After)
LSL
15.00000
Target
16.00000
USL
17.00000
Individual Detailed Reports
Density (After)
Specification
Lower Spec Limit
Spec Target
Upper Spec Limit
Value
15
16
17
Portion
Below LSL
Above USL
Total Outside
% Actual
7.0000
3.0000
10.0000
Long Term Sigma
-3s
14
Mean
+3s
LSL
Target
USL
15
16
17
Sigma = 0.62229
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Capability
CP
CPK
CPM
CPL
CPU
Portion
Below LSL
Above USL
Total Outside
Index
0.536
0.470
0.525
0.470
0.602
Lower CI Upper CI
0.461
0.610
0.377
0.562
0.454
0.597
0.377
0.562
0.495
0.707
Percent
7.9371
3.5566
11.4938
PPM
79371.268
35566.446
114937.71
Sigma
Quality
2.909
3.305
2.701
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Deming’s Responsibility
Assignments
Statistical Control?
Yes
Good
Results?
Yes
No
No
No
Action
Manage- Local
ment Work
Force
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Process Improvement
Experimental Design
Manipulate process inputs.
 Control for outside
variables.
 Randomize.
 Replicate.

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Summary
 By carefully observing the current
process, assignable causes of
variation were found and
eliminated.
 Although the process was
brought into a state of statistical
control, the process was not
capable of meeting specifications
or customers’ needs.
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