Stat 512 – Statistical Methods

 

Class meetings:          TR 5:10-7:00 (Statistics Studio, 02-206)

Instructor:                  Beth Chance                            Office:  FOE 25-103

Office phone:             756-2961                                

Email:                         bchance@calpoly.edu (often the best way to reach me quickly)

Office hours:              M 9-10am, T 3-4pm, W 11-12pm (held in the Statistics Studio), Th 1-2pm

also by appointment or any time my office door is open

Course webpage:       http://statweb.calpoly.edu/chance/stat512/  and Blackboard (my.calpoly.edu)

Course listserv:          

 

Overview: Statistics can be defined as the science of reasoning from data. Data and statistical reasoning abound in our everyday lives, and the discipline of statistics makes great contributions to the scientific enterprise and to many aspects of life in our technological society.  This course will introduce you to the nature of statistical reasoning and to basic statistical methods including exploratory data analysis, confidence intervals, tests of significance, two-way tables, regression and correlation, analysis of variance.  We will also focus on different data collection methods and their consequences for analysis and the scope of conclusions that can be drawn.

 

Text/Materials:        

·        Statistical Methods for the Social Sciences, 3rd edition, Agresti, A. and Finley, B. Prentice Hall, 1997.

·        Selected materials from Investigating Statistical Concepts, Applications, and Methods (ISCAM), Chance, B. and Rossman, A. (2005). 

Available from instructor.

 

You should purchase the textbook and a three-ring binder for storing and organizing handouts.  You must also have a scientific calculator, PC formatted CD-RW or flash drive, an email address, and access to the internet and Minitab software access outside of class.  Please bring your binder and calculator to every class session. 

 

Statistical Packages/Calculators:  We will be using the Minitab software package (version 14) for data analysis and exploration.  You will be given instructions for how to use Minitab, Excel and Microsoft Word as needed for this course.  You will need access to Minitab outside of class.  Minitab is freely available in the studio and all IT computer labs (see open hours).  You can also download a copy from the Technology panel of my.calpoly.edu (under Windows).  Please see me or ask through the Blackboard Discussion Board or course listserv if you aren’t familiar with the statistical options on your calculator.

 

Class structure:  The class time will be a mixture of lecture, student investigations, and computer labs.  Most class discussion will center around investigations from instructor handouts as a supplement to your reading of the textbook.  You will be responsible for material from both sources.  You should prepare for class by reading the assigned sections in the textbook, doing the practice problems (see below), and previewing the upcoming investigation (often beginning the investigation before coming to class as assigned).  Come to class with questions from the textbook and investigations.  We will also spend time in class reviewing the practice problems and answering questions from the readings.

 

Practice Problems:  A small number of practice problems will be assigned at the end of class to be submitted prior to the next class.  You will need to use Blackboard to view the text of the questions.  These will be informal assessments to practice the material learned in that class.  The goal is to help you immediately apply your knowledge and to determine where you still have questions.  Your work can be submitted either through Blackboard (the best option if it works for us), through email (please use “Stat 512 PP” in the subject link), or as a hard copy to my office by 3pm on the day due.  Each problem will be graded 0 or 1 with 0 = no/minimal effort, and 1 = substantial effort.  After you submit your answers, Blackboard or I will supply feedback.  If you use Blackboard, you do not need to submit many of the graphs and computer output but should briefly describe the visuals. 

 

Homework Assignments:  Homework problems will be due approximately once per week.  Unless instructed otherwise, these will be due by noon on Friday.  You can submit them via email, in class, or to the cardboard box outside my office door (on the floor). For hard copies, you should fold the assignment in half lengthwise and include your name, section number, and assignment number on the outside.  Include a summary of the problem statement before each solution to aid your later review. Your work is easier to grade if you write on only the front side of each page. To ensure no pages are lost, you are required to staple all pages together.  Your writing should be legible and your spelling and grammar should be correct.  You are encouraged to work together on assignments but your solutions must be written up individually. Students are also encouraged to ask questions on the assignments (ahead of time!) inside and outside of class.  If you receive a large amount of information from another source, e.g., me, another student, another book etc., you must state the reference in your write-up. If I determine assignments are too similar, the one score will be divided among the papers. Late assignments will not be accepted, but I will review previous assignments with you if you complete them after the deadline. Your lowest homework score will be dropped.  You are advised not to use this up too early in the quarter.  The main requirement for all problems is that you explain your answers. Often, questions may have more than one correct answer so several answers will be accepted as long as they are justified. You should also state any assumptions that you make. You will also be given partial credit for your work, so it is important to at least attempt each problem.  Graded assignments will be returned in class or can be picked up from the wood box on the wall outside my office (DO NOT put ungraded work here!).  Homework solutions will be posted on the course webpage Friday afternoon.

 

Term Project:  You are to complete one data collection and analysis project (details to follow).  You are highly encouraged to work together in groups (up to four people).  Groups will make either an oral or poster presentation of their project to the rest of the class during the last class meeting.

 

Exams:  There will be one midterm exam (tentative date listed below) and one comprehensive final.  You may make up an exam only with a written medical excuse.  The exams will be a combination of open-ended questions and computer analyses and may include a take home component.  A review sheet will be supplied prior to each exam.

 

Grading policies: In order to give you a variety of opportunities to demonstrate your learning, your course grade will be determined by the following components, with relative weight as indicated:

Practice problems and class participation (10%) Homework (20%)

Term project report and presentation (25%)         Midterm exam (20%)             Final exam (25%)

Be aware that the abilities to understand concepts, interpret results, explain reasoning, and communicate findings are more important than computational manipulations or rote memorization in all of these areas.

 

Advice: With apologies to David Letterman, I offer the following “Top Ten” suggestions to improve your learning in this course:

1.     Come to class.  Due to the interactive nature of the classroom learning environment, most students find that attending class regularly is essential to learning the material.  Please make every effort to attend class and to arrive on time so as not to disrupt the learning of others. If you are late to class, enter quietly in order to minimize distractions. Naturally, you are responsible for material covered and announcements made during classes that you miss.

2.     Actively participate.  Not only will this help you to learn the material and perform well in the course, but it will also produce a much more enjoyable learning environment for all of us.  Participating in class will typically entail contributing to discussions and working on hands-on activities that we design to help you investigate and learn the material.  Some of these activities will ask you to work cooperatively with a partner or group.  It will be your responsibility to ask for clarifications of any terminology and/or concepts as the course progresses, even if it is “hey what?” Be willing to learn from your mistakes.

3.     Prepare for class.  Preparing for class will typically involve reading the chapter in the book to be discussed that day and reviewing previous notes to see where you have questions.  You should also start assignments, like homework problems, several days before the due date so that you may ask questions during class and in office hours, as well as reflect on the relevant material as it is discussed in class.  You are expected to spend 8-12 hours per week outside of class for this course.  It is very important that you keep on top of things and do not fall behind.

4.     Be courteous.  Pay attention during class. Do not read the newspaper or talk to your neighbor (unless I have asked you to work together). I would much rather you interrupt me with a question then hold your own private conversation. If you cannot stay awake, we would all be better served by your leaving quietly and catching up on your well-deserved sleep. Do not surf the web or check e-mail during class. It’s fine to do this before class starts, but please give me your full attention when we begin class. Do not allow your cell phone to ring during class. Do not leave class early.

5.     Ask questions.  Please feel free to ask questions during class.  This includes questions that arise from your reading, because I will not attempt to present all of the material that you read about.  It also includes questions that come to mind based on class activities and discussions.  Rest assured that if you ask a question, the answer will probably benefit many students in addition to yourself.

 

6.     Defend your arguments.  You will find that there are not sharp distinctions between right and wrong answers for many of the issues that we will discuss. This does not mean, however, that all arguments are equally valid. What matters is the degree to which you defend your position with supporting evidence.

7.     Work together.  You will find that you can learn a great deal from your peers. Some of your assignments will ask you to work together in pairs or teams, but feel free to ask for advice from your peers at other times as well. Take advantage of the opportunity to see topics from several viewpoints.

8.     Use office hours and email.  Please come to visit me during office hours.  You may come with specific questions or general ones.  You may bring questions about an assignment, questions about something mentioned in class, or questions about anything at all.  Feel free to stop by at times other than office hours as well.  You will also find e-mail (to me and/or to the rest of the class) to be an efficient way of communicating questions. 

9.     Have fun!  I sincerely hope that you will enjoy both the subject matter of the course and the learning process.  By all means you should try to enjoy the readings and discussions. I also hope that you will enjoy our class discussions and participate in them substantially.

10.  Think!!  Please be prepared to open your mind as you investigate new ideas and think about familiar ones from new perspectives.

A common theme emerges from these suggestions: You are responsible for your own learning. I see our responsibilities as your instructors as providing you with an environment rich with activities, discussions, and feedback that foster your learning experience.

 

Tentative Schedule: The following is a tentative schedule, always subject to change.  Please read the indicated material prior to attending that day’s class session. 

Day

Date

 

Topics

Have Read

PP due next class

1

9/20

T

Comparisons and Conclusions

Ch. 1, p. 12-17, 21-22

PP 1

2

9/22

R

Confounding, Designing experiments

Start Ch. 3

PP 2

3

9/27

T

Statistical significance, Sample size effects

 

PP 3

4

9/29

R

Quantitative data, Minitab

Ch. 3

PP 4

5

10/4

T

Randomization test, Statistical significance

 

PP 5

6

10/6

R

Sampling, Sampling Distributions

Ch. 2, Sec 4.3- 4.5

PP 6

7

10/11

T

Probability models and inference

Sec 4.1, 4.2

PP 7

8

10/13

R

Tests of significance

Ch. 6

PP 8

9

10/18

T

Confidence Intervals

Ch. 5

PP 9

10

10/20

R

t-procedures

Ch. 6

PP 10

11

10/25

T

Review

 

Review Qs

 

10/27

R

Midterm Exam

 

 

12

11/1

T

Comparing populations

Ch. 7

PP 11

13

11/3

R

Chi-square tests

Ch. 8

PP 12

14

11/8

T

ANOVA, Multiple comparisons

Ch. 12

PP 13

15

11/10

R

Randomized block design

 

PP 14

16

11/15

T

Two quantitative variables

Sec 9.1, 9.2

PP 15

 

11/17

R

Inference for regression

Sec 9.3-9.7

PP 16

17

11/22

T

Multiple Regression

Sec 11.1-11.4

PP 17

 

11/24

R

Happy Thanksgiving!

 

 

18

11/29

T

More multiple regression, odds ratios

 

PP 18

19

12/1

R

Presentations

 

 

 

12/9

F

Final Exam 7-10pm

 

 

 

Dates to Remember:

Last Day to Add  9/27

Last Day to Drop 9/28

Term Project

 

Goal:  To collect, describe, and analyze data to answer two questions of your choice. This will allow you to apply the skills you learn in this course to the world around you which will in turn enhance your appreciation and retention of the material.

 

Teams:  For the class projects, you will work in groups of 1-4.  It is up to the members of the group to make sure everyone contributes equally. Teams should be formed by the end of week 2. Make sure you obtain phone numbers and email addresses for each other.  If you think finding meeting times will be difficult, you may want to start dividing the workload into subgroups.

 

Topics:  You are free to choose your own questions.  The questions may be related to your major or some other topic of interest.  You should choose a topic so that it will be straightforward to gather the data. The easiest approach will be to design an experiment to compare two groups but the only rule is to make sure the topic is interesting to your group!  Be creative!  We will discuss some previous topics in class, and some previous project topics can be found on the course web pages.  You will want to collect lots of data and then narrow in on two hypothesis pairs later.  After the topics are selected, most of the work for the projects will take place outside of class.

 

Project Reports: The goal of the project reports is to keep you thinking about the projects as the term progresses.  Keep in mind that your project may change and evolve as the course progresses.  Still, with each project report I would like to hear about your progress and ideas.  Turn in one project report for each team, including team members’ names and previous project reports, preferably typed.  Below are some guidelines on what I would like to see in each report.

            The first project report is due Oct. 11. For this report you should identify your topic/questions of interest, the variables you plan to measure, the population you plan to draw conclusions about, the sample and sampling frame you plan to use (if applicable), and the type of study (e.g., observational study/survey or experiment). 

            The second project report is due Oct. 18.  Your data collection techniques should be more clearly defined.  If an experiment, give your tentative design.  If a survey, give the preliminary questionnaire.  You should indicate why this study is appropriate to answer your question and what precautions you will take (e.g., nonresponse, nonsampling bias, wording). 

            The third project report is due Nov. 22.  You should have finished collecting your data. Include a description of your observational units, your variables, their measurement units, possible ranges/responses of these variables, as well as preliminary descriptive statistics. You should also specify two research questions/sets of hypotheses that you plan to test using your data.   Indicate which set of statistical procedures you believe you will use.  Include a justification for that choice of procedure. You should also outline how the remaining work will be completed (who, when).

            Rough Draft (optional).  If you turn in a rough draft by Nov. 29, I will review the paper, providing comments and suggestions for improving your final grade and presentation.

Final Reports: Final reports are due on or before Dec. 2.  Reports must be typed.  Turn in one report per group and include previous project reports. Incorporate computer output into the body of the paper.  Raw data should be emailed to me as an attachment.  You may assume your audience will understand all statistical terminology.  Make sure the final report includes at least:

 

- Title page with all group member names, Fall, 2005.

 

- Statement of Purpose: One to two sentences outlining the topic of the study

 

I. Introduction

Why did you choose this topic?  What did you expect to find?  Have similar studies been done elsewhere?  Why should the reader be interested in your results and continue reading?

 

II.  Data Collection Methods

How did you collect the data?  What were the observational units?  What groups did you compare, how did you find them/form them?  Type of study? What was your response variable?  How were these variables measured?  What additional “controls” did you exert on the study?  (e.g., did you only observe people writing or did you take any behavior such as throwing a football as indication of handedness?) Any “operational definitions”? (e.g., did you field test any of the questions on a test group to see if the wording was clear?). Be especially clear on the role of randomness in your study.  Are there any other potential sources of sampling or non-sampling errors? Any other unexpected results?  Did anything go wrong during the course of the study?  (Note: You can never give me too much detail in this section!)

 

III. Analysis of Results

Descriptive Statistics: You will need to make choices as to which numerical and graphical summaries are most relevant.  Make sure you integrate the computer output into the body of the report and include discussions of how you are interpreting the message in these summaries.  In your discussion you should fully describe your sample, sample size, and report the sample statistic and whether it supports your conjecture. Make sure all figures and graphs are clearly labeled.

Inferential Statistics: In carrying out the test(s) of significance, remember to: state your hypotheses in symbols and in words; justify your choice of procedures and comment on the validity of the methods (technical conditions); perform appropriate follow-up analyses (e.g., multiple comparisons, expected cell counts) and confidence intervals; state your conclusions in context.  Pay particular attention to whether you can generalize your sample to a larger population and whether you can draw cause and effect conclusions.

 

IV. Conclusion

Summarize the results of your study.  What did you learn?  Did the data behave as you expected?  Critique the methods used to collect the data.  Is there anything you would do differently next time?  How might this affect the conclusions of the study?  What similar questions might someone chose to investigate in the future to build on your results?

 

Appendix:  Access to raw data (email), previous project reports

 

Grading Criteria for Final Report:

10%: Quality of written report

20%: Design of survey/experiment – was data collection adequately explained, were the appropriate data collected to answer the questions posed, was the topic original? 

25%: Correctness of statistical analysis and checks of technical conditions

20%: Appropriateness of interpretations of the results of the statistical calculations and conclusions (is it a cause and effect relationship? what is a reasonable population?)

25%: Presentation – details to follow