## Preface

Probability and statistics are important subjects because so much of what we take for granted is based on them. The insurance and gambling industries would not be possible without probability theory. Much of modern finance relies on probability and statistics. And much of modern science, both physical and social, would grind to a halt without the tools of statistical analysis.

Given its importance, it is unfortunate that so many students find statistics a difficult course. Some find it challenging because they lack basic math skills. Even though an introductory-level statistics course does not require mathematics beyond what a high school freshman or sophomore should be able to do, many adults and college students do not have even that level of math competence. Others find it difficult because they try to get through the course with brute memorization. Statistics is a problem-solving subject, and a strategy of memorization will not work well when problem-solving skills are required.

Statistics is a subject that tries to make students think in new ways, to see the reality around them from perspectives they have not used before. Once you understand statistics, you should see the world in ways you presently do not know exist.

A good introductory course should help you become a competent consumer of statistical information. As a competent consumer of statistical information, you will be able to understand what an author is trying to do when that author gives you the results of a statistical analysis. While taking an introductory course, you will learn to do some simple statistical analysis, but you will not learn enough to be a competent producer of statistical information. That requires additional study.

Even though probability and statistics are mathematical subjects, the emphasis in an introductory course should not be on the mathematics but on the intuitive understanding that is behind the mathematics. Instructors attempt to help students get to that intuitive understanding with a generous dose of problems and assignments worked with computer statistical packages. However, there is no magic way to get the student to the "ah-ha" moment when suddenly it all starts to make sense.

I taught introductory statistics for college students off and on for almost 40 years. During that time I wrote many homework assignments and many quizzes and tests. The problems from these assignments, quizzes, and tests form the major part of this website. Statistics is something you learn by doing, not by passively reading. I have added short introductions and explanations but these short explanations are not a substitute for a real textbook. This site will never be developed enough to serve as an independent textbook, but it may be able to serve as a supplement for a variety of textbooks.

I apologize in advance for the typos and errors that remain in this material. If you find some of them, please tell me about them at schenk at saintjoe.edu. Also, though I have included answers for some of the questions, there are many problems and questions that still do not have an answer key. If you work them and would like me to check them, I will if I can use the results as part of an answer key. Finally, I am open to suggestions for improvements as long as the benefits exceed the costs.

R Schenk
Summer 2010

(I intend that only material I wrote and developed appear on this website, but it is possible that a few items that I used from old testbanks or textbooks for homework or quizzes may be included. If you find anything that appeared in another text, tell me and I will remove it.)