Week 5
Employing the Normal
Distribution
Operations and production managers often use the normal
distribution as a probability model to forecast demand in order to determine
inventory levels, manage the supply chain, control production and service
processes, and perform quality assurance checks on products and services. The information gained from such statistical
analyses help managers optimize resource allocation and reduce process time,
which in turn often improves profit margins and customer satisfaction.
Based on your understanding of the characteristics of the
normal distribution, examine the chart below.
Process A standard deviation is .9, Process B standard deviation is 1.4,
and the mean of both processes is 12.
Contribute to our discussion by posting a response to ONE of the
questions below.
Do either of the processes below fit a normal distribution? Why or why not?
Which of the processes shows more variation? What does this mean practically?
If the product specification quality limits were 12 +/- 3,
which of the processes more consistently meets specification? Explain why.
If the product specification quality limits were changed to
12 +/- 6, is quality loosening or tightening?
Which process would benefit the most from this change?
Are there processes at your place of employ that you believe
follow a normal distribution? If so,
describe one. Why do you believe it is
normal?
Hang Up and
Drive
Check out this snippet from Family Circle magazine (January,
2009, Liz Plosser):
Motorists who talk on
a cell phone while driving are 9% slower to hit the brakes, 19% slower to
resume normal speed after braking and four times more likely to crash.
Interesting, eh? Need
more information? Sorry, that’s all the information this article provided. So,
what can we conclude? How reliable are these results? Can you believe what the
author tells you? Why or why not?
Pretend you’re a
manager for one of the major cell phone service providers in the U.S. You’ve
been asked by a major news magazine to speak to these “accusations.”
What would you say? Use your knowledge of “statistics for managers”
to level some well-founded criticisms of the conclusions above.
Careful! We cannot
use personal opinions to battle statistics like these! Instead, you must explain
why the numbers reported in Family Circle may, or may not, accurately represent
the population of U.S. drivers. There are 100 possible answers to this
conference topic.
You need only provide
a single idea, to get the conversation rolling. Leave some material for others
to contribute. Be sure that your contribution explicitly references what we’ve
read and practiced in the class so far.
It is your classmates’ job to support or refute what you’ve said.
