Fall Semester 2003

Our eleventh time in lab, Wednesday December 10, 2003
Dec  5, 2003

Due today
Reading Assignment: Chapters 11 (Time series) and 12 (Quality Control) in the text.

Starting today
LAB ASSIGNMENT EIGHT (the questions listed below).

Due next time (a week from today)
Reading Assignment: Nothing. (The semester is coming to an end.)

What is the lab assignment?
Answer the questions below also indicating the page(s) in the book where the answer can be found.

When is it due?
Check the What's Due? page for details.

What's the best approach to this assignment?
Read the book, work through all the experiments.

Here are the questions

Chapter 11: Time Series.

  1. Use the Dow.xls workbook, plot the time series and answer the following question: "How variable are the average Dow values from one month to another?"

  2. Why in the process of your analysis might it be useful to transform the values to stabilize the variance? What do you do?

  3. What are "lagged values" and what significance do they have in our experiment? What is the autocorrelation function and what's it used for?

  4. Describe some typical ACF patterns. Does any one of them applies to the Dow example?

  5. What are moving averages? What is simple exponential smoothing? In the Dow example (the section on forecasting to guide decisions) how do you calculate the buy or sell signal for each month? Is exponential smoothing well suited to predicting short-term market activity? Why or why not?

  6. Describe the basic idea behind two-parameter exponential smoothing.

  7. The example on page 446 starts with the question: "Is beer production seasonal?" What does the chapter do to answer this question and what is the answer?

Chapter 12: Quality Control.

  1. What is the purpose of a control chart?

  2. Where and how did statistical process control originate?

  3. (Fill in the blank) From the book: "SPC is a methodology for distinguishing whether variation is _________ or __________." Explain the relative significance (and remedies).

  4. What is the difference between variable and attribute charts and when/why are they used?

  5. Briefly (and completely) summarize the example presented in the book for calculating control limits when the standard deviation is known.

  6. What case-study does the workbook Coats.xls refer to? What is the conclusion? How is it reached? Is it justified?

  7. How is the C-chart used in the book to help with SPC and what is the monitored process?

  8. What are the relative merits of P-charts?

  9. How do you create control charts for processes that cannot be neatly divided into subgroups?

  10. What is a Pareto chart and when is it useful?

Last updated: Nov 10, 2003 by Adrian German for A113