Statistics 220
Basic Statistics

Course Introduction

Overview

Statistics 220 is a non-mathematical introduction to the basic ideas and methods of statistics. In this course, you will learn a variety of basic statistical terminology and statistical reasoning used both in society and academia. We'll emphasize conceptual understanding over more technical aspects of statistics.

This course covers a wide-range of topics, including

• graphical and numerical descriptions of data (histograms, means, and standard deviations);
• an introduction to properties for normally distributed data and normal approximation;
• ideas around samples and chance error;
• correlation and regression models; and
• elementary probability.

We'll also look at chance variability as it applies to sampling and interpreting estimates; explore the basic concepts of statistical inference; and introduce confidence intervals and several classical tests of significance (hypothesis testing).

You are probably familiar with the phrase "information age." This term has made its way into mainstream vocabulary, and its increasing use is right in line with an increasing emphasis on the collection and analysis of data. The use of statistics is not limited to publications in academic research journals; today, you can find statistical methods discussed almost daily, in studies reported in newspapers, magazines, many company reports, and news broadcasts. The increased use of statistical methods is probably the result of several influences, but the mainstream occurrences are largely the result of the proliferation of larger electronic data storage capabilities and computer access by more individuals. Computers are readily available, and they provide ever more capacity for data storage, and easily usable data processing functions. Many statistical analysis functions are automated in menu-driven software packages available to a wide audience.

So, why take a statistics course? There are several reasons people take this course, including: "I have to because it is a requirement for my major," "I need to in order to advance at work," "I want to, because I see more and more uses of statistics and I don't really understand the methods." Another answer, which I hope this course will help you discover, is that statistics is now an essential tool for communicating certain information. Studying statistics will give you access to powerful methods for problem solving and analysis, as well as the ability to make informed decisions about things you hear or read.

Statistics is a science, with methods that allow us to make numerical statements about a variety of problems. The authors of the textbook we'll use (Freedman, et al., 2007) list a number of classic questions that statistical analyses can help us answer, including the following:

• What are the effects of new medical treatments?
• What causes the resemblance between parents and children, and how strong is that force?
• Why does a casino make a profit at roulette?
• Who is going to win the next election? By how much?
• How many people are employed? Unemployed?

After taking this introductory statistics course, you will be in a better position to understand reported numerical information, and to question the work done by others. You will be able to form your own conclusions about to information you hear or read in everyday media or at your place of work.

Course Prerequisites

There are no explicit prerequisites for this course. It will help, however, if you are proficient in the skills at the level of intermediate (high school) algebra. If it's been a long time since you took any math, you may need to review some basic algebraic techniques.

Course Objectives

After you have completed Stat 220, you will be able to

• summarize single variable data sets by drawing histograms and computing averages and standard deviations;
• interpret the information in histograms drawn by yourself or others;
• use computed averages and standard deviations to apply normal approximation methods;
• relate data to a standard normal distribution or percentiles when appropriate;
• define measurement error and the idea of chance error versus bias;
• plot points and lines to look at relationships between two variables;
• compute correlation coefficients and relate the correlation coefficient to the effect of regression;
• perform simple linear regression analysis, including finding the equation for the regression line;
• relate the idea of chances to elementary probability rules, and extend these concepts to setting up correct chance models in order to make a statistical inference;
• compute standard errors and confidence intervals as measures of reliability; and
• set up and interpret hypothesis tests, using z-tests, or (chi-square) tests, in order to make inferences about populations based on information from samples.

About the Online Environment

Your online course offers several advantages to the traditional classroom, including the comprehensive Online Student Handbook, the ability to communicate electronically with students and with your instructor, and links to a rich array of online resources.

Online Student Handbook

This handbook answers questions about your online learning course, such as how to purchase your text, schedule an exam, obtain a transcript, and get technical help if you need it. The handbook also provides additional resources, such as how to order books or journals from the library and how to study for an online course.

Communication with Your Instructor and Student Peers

• Online Discussion Forums, designed by the University of Washington award winning Catalyst team, allow you to communicate with other currently enrolled students and with your instructor. You can use the General Discussion Forum to post questions, share resources, or engage in conversations about topical issues.
• E-mail is a quick and efficient way to communicate with your instructor about feedback you've received on an assignment. In fact, many online students comment that they get more support and individual attention about assignments in their online class than in a traditional classroom.

Online Resources

As an online student, you have access to a wealth of Web resources compiled to provide fast, easy access to information that supports your online learning experience. Organized by subjects, Online Resources link you to sites with help for writing and research, study skills, language learning, and library reference materials. All links have been assessed for credibility and reliability, and they are regularly monitored to ensure their usability.

Required Text and Materials

• Freedman, David, Robert Pisani, and Roger Purves. Statistics, Fourth Edition. W.W. Norton & Company, Inc. 2007. ISBN: 0393929728

The required textbook is extremely important; it is your primary source of information in this course. While it is generally easy to read, this textbook was written much like a novel, and you need to read each section completely. This is different from many math and statistics texts, which you can skim or flip through, looking for key words or formulas that will help solve particular problems. The authors provide many examples, some of which can seem complicated. You may need to read certain sections more than once to understand them. The online lessons will help to explain some of the more confusing topics.

While we won't explicitly cover chapters 1 and 2 in the text, I recommend you read them. They provide an introduction to elementary concepts of study design, which will help provide a context for some of the methods we'll cover throughout the course.

Required Materials

• A basic calculator that includes a square-root function key
• Graph paper and a ruler may come in handy for a few of the problems in chapters 7-12.

About the Course

This course covers chapters 3-14, 16-21, 23, and 26-28 in the textbook. The online course materials include eight regular lessons, as well as two lessons that will help you prepare for the midterm exam and final exam. In addition to graded assignments and exams, this course includes key terms, practice exercises, and discussion forums to reinforce learning and supplement the material.

 Key Terms

Something else that will help you prepare for the exam is the glossary of terms I will ask you to begin in Lesson One. True, the textbook contains a glossary (pp. G–1 through G–13), but a definition alone rarely satisfies our need to understand the context in which a word takes on its richest meaning. You will use the list of key terms and concepts in each lesson to create your own glossary or to add to the glossary in the back of the book. By the time you are ready to take the final exam, you will have a rich resource of annotated key terms from which to study and review.

Practice Exercises

The recommended practice exercises are listed at the end of each main section in the lessons. These exercises are for practice; they consist of problems from the exercise sets in each chapter of the textbook. You will be able to check your answers in Appendix A of the textbook. These problems are not required, but I highly recommend you try to solve them. They are similar to the problems I have assigned as written problems for grading. If you have any trouble with the recommended practice exercises, contact your instructor with questions. Be sure to reference your questions with the problem number and page number in the text. If you are e-mailing a question, include in your message all the steps you have completed, so your instructor can see where you are having trouble. If you leave a phone message, be sure to reference the exercise page and number so your instructor can be prepared when calling you back.

About Discussion Forums

The Discussion Forum enables us to simulate one of the features of a classroom setting; we'll be able to share our questions and ideas through threaded online discussions. You will find a Discussion Forum linked from your Course Syllabus

In this course, you are encouraged to exchange information, ideas, and questions about your assignments using the relative discussion area. This forum is for your benefit. The instructor checks the forum regularly and you can expect some feedback, comments, or answer to specific assignment questions. The online discussions not only allows you and your classmates to share knowledge and help each other learn, but you may find classmates a useful resource for answering questions.

About the Lessons

Each online lesson consists of a reading assignment from the textbook, a commentary, recommended practice exercises, and a written assignment that you will submit for grading.

• In Lesson One, we'll talk about basic descriptive statistics, including how to create histograms, compute the mean and standard deviation, and work with normal approximation for data.
• Lesson Two covers measurement error, plotting points and lines, and correlation.
• In Lesson Three, we'll look at regression models.
• Lesson Four is an introduction to probability and chance.
• In Lesson Five, you'll prepare for and take the midterm exam, which covers Lessons One, Two, Three, and Four. This lesson includes a practice midterm, which you will be able to grade for yourself, to assess your readiness for the actual exam.
• Lesson Six discusses chance variability.
• In Lesson Seven, we'll examine sampling, including sample surveys and chance error in sampling.
• Lesson Eight continues the discussion of sample, including accuracy of percentages and averages.
• Lesson Nine covers tests of significance, including tests for population averages and percentages, and chi-square ( ) tests.
• In Lesson Ten, you'll prepare for and take the final exam, which emphasizes material in Lessons Six, Seven, Eight, and Nine.

About the Assignments

Each of the written assignments consists of six to nine problems, selected from the review exercises at the end of the chapters, that represent each of the concepts introduced in the lesson. Except for the simplest of problems, be sure you show your work along with the final answer, when you submit your assignment to your instructor. A fair number of the assigned problems are presented as true/false or multiple choice questions, which may make it tempting to just give a bottom-line answer. If you only provide a final answer, however, and do not show your work, the instructor cannot provide you with any feedback on where you might have gone wrong. The written assignments will be graded on a 4.0 scale. See the About the Instructor page on your course syllabus for assignment submission details.

About the Exams

The midterm exam follows Lesson Five and covers Lessons One, Two, Three, and Four. The final exam follows Lesson Ten. The final exam is cumulative, but emphasizes the remaining lessons following the midterm.

Do not take the exams until you have received back all assignments that precede the exam. The exams are closed-book, so you may not bring your textbook; but you may use one 8.5" x 11" page of notes (double-sided) that you created while studying for the exam. You may also use an ordinary hand-held calculator.

The exam problems are multi-part, short-answer problems, similar to the problems in the written assignments. You must show your work to get credit; you can get partial credit for the correct (or nearly so) setup of a problem, even if your final answer is incorrect. You will have two hours for each exam. The exams will be graded on a 4.0 scale.

Grades and Deadline

Written assignments and exams are graded on a 0.0 to 4.0 scale. The eight written assignments averaged together count for 20 percent of your course grade. Each exam (midterm and final) counts for 40 percent of your course grade.

Eight written assignments	20%
Midterm exam	40%
Final exam	40%

Deadline

This course is self-paced and designed to be completed in three months. Complete and submit the Assignment Due Dates calendar linked on your syllabus page to plan your due dates for assignment submission. If you need to have your final course grade turned in to the registrar by a certain date, plan ahead. Work is graded on a first-come-first-served basis. If you wait until close to your course deadline to submit multiple assignments, they may not get graded in as timely a manner as you would like.

Allow two weeks after submitting your final for Distance Learning to process your grade. Allow even more time if you are taking the exam with a proctor. We cannot get through the process any faster. If your schedule turns out to be particularly tight, you may request a letter from your instructor indicating that you have completed the course and your course grade. You may be able to use this prior to having your grade posted to your transcript.

Study Tips

The amount of work required to complete this course varies for each student. In general, however, learning statistics is much like learning mathematics: the process of working problems regularly is what cements the ideas and helps you master the concepts. If you try to sit down once a week to do a lesson, it may be more difficult than if you work a shorter amount of time, several days a week.

The following study tips may help you learn the material in this course:

• Read the introduction and objectives for each lesson to help you focus as you read the textbook.
• Read the assignment material in the textbook. As I mentioned earlier, the textbook is meant to be read more like a novel; that is, you'll need to read the chapters in their entirety. You may be used to skimming through math books, looking for the formulas needed to solve a particular problem; that approach may not work for this course.
• Read through the related online material.
• Have a pencil in your hand and work through the textbook examples as well as the examples in the lessons. Make sure you understand the steps to each solution.
• Draw pictures! Many times in this course, a picture can help clarify what is being asked. I've included illustrations throughout this course.
• If you don't understand something, or are getting frustrated, send your instructor an e-mail. Sometimes you can get hung up on little things (that may seem like big things) that can prevent you from making progress. A point of clarification or explanation from the instructor can often get you on your way.
• Do not take the exams until you have received back graded assignments for all material on the exam. This will allow you to incorporate any instructor feedback as you prepare for the exams.

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