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Can you draw a straight line without a
ruler?
For Instructors: Do you have the pass
code for this activity?
For Students: Have you read the
Instruction
for Participation page?
The Problem
Can you draw a two inch line without a ruler?
Variation and bias are two natural occurrences in
data. Consider Cola bottling process; filling
cola in 12 oz. cans. The target amount is 12 oz
in each can. However, the actual amount filled
is rarely exactly 12 oz. They vary around the
average amount filled by this process, which may not
be 12 oz. There is a difference between the
target amount and the average amount filled by the
process. This is the bias. And from bottle
to bottle the actual amount filled varies. This
is variation. In this activity you will simulate
a similar process by drawing a 2 inch line 10 times.
Each line you draw is similar to filling a bottle.
The variation among the ten line segments is the
within subject (or within process) variation.
The difference between the two inch lines and your
average line length is the within subject (or within
process) bias. In addition there are differences
from student to student variation. This
variation is the between subject (or between process)
variation. In a manufacturing process, our goal
is to reduce bias and minimize variation. So,
how well can you draw a two inch line segment?
Is your process better than others?
Objectives
1. Learn the concepts of bias and
variation presented from any process.
2. Learn within subject
(within process) variation and between subject
(between process) variation.
3. Learn ideas
of reducing bias and minimizing variation.
4. Learn how the sampling distribution
of sample mean is applied in a process control.
5. Learn analysis of variance
technique.
Key Concepts
Target, process mean, bias, within subject
variation, between subject variation, sampling distribution
of sample mean and analysis of variance.
Related Topics
The data
collected from this activity can also be used for the
following topics later in this course: Required Equipment
• Activity pass code (provided by the instructor)
• Piece of paper and pencil
• Ruler
• Internet connection
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