Statistics Spring 2007

Introduction Dr. Robb T. Koether Office: Bagby 114 Office phone: Home phone: (before 11:00 p.m.) Office hours: 2:30-3:20 MTWR  Other hours by appointment Web page: staff/robbkhttp://people.hsc.edu/faculty- staff/robbk

The Course The class meets in Bagby 106 at 1:30 - 2:20 MTWF. The text for the course is Interactive Statistics, 3rd ed., by Martha Aliaga and Brenda Gunderson.Interactive Statistics, 3rd ed. The web page for this course is at Course information is also available through Blackboard. Blackboard

Introduction Syllabus Lectures Assignments Page xi – Interactive Exercises Page xvi – Graphing Calculator

Grading There will be  Weekly quizzes  Some Excel assignments  Three tests  A final exam

Grading In the final average, these will have the following weights: CategoryWeight Average of quizzes & Excel30% Average of the tests50% The final exam20%

Homework The homework is the most important part of this course. Learning mathematics requires gaining knowledge and understanding, but more importantly doing mathematics is a skill. You should not expect to acquire a skill by listening to a lecturer talk about it. It takes practice. Do all of the homework every day.

Homework More importantly, do not put off doing the homework until the night before the quiz. You will not be able to learn that much material in one night. Most importantly of all, do not put off doing the homework until the day before a test. By then it is too late to learn it.

Homework At the beginning of each class meeting, I will spend up to 10 minutes working one or two homework problems in detail from previous assignments. You may request a problem that you would like to see worked. Of course, outside of class, I will help you with as many problems as I can.

Quizzes Each Tuesday, after going over homework problems, there will be a 10-minute quiz. The quiz will contain 1 to 3 questions taken from the previous week's homework assignments. The problems will be copied verbatim from the book.

Excel Assignments From time to time, as appropriate, I will assign small projects that will be worked using Microsoft Excel. You will be allowed and encouraged to work in pairs on these assignments. These will be graded with the same weight as the quizzes.

Tests The test schedule is as follows: TestDateCoverage #1Fri, Feb 16Chapters 1, 2, 3, 4 #2Fri, Mar 23Chapters 5, 6, 7 #3Fri, Apr 20Chapters 8, 9, 10, 11

The Final Exam The final exam will be cumulative. It will be given in this classroom at the time stated in the exam schedule. Everyone must take it. It will not be rescheduled. Do not schedule a flight home before the exam! You will lose your ticket.

Attendance Attendance will be checked at the beginning of each class. Two late arrivals will be counted as one absence. The only valid excuses for missing class are  An illness which includes a visit to the Health Center or a doctor  An approved college activity  A true emergency  Any absence excused by the Dean of Students

Attendance Sending me an or leaving me a voice message does not excuse you from class.

Attendance When assigning final grades, attendance will be taken into account. AbsencesAction 0 – 2Grade bonus 3 – 5Neutral 6 – 8Grade penalty > 8Withdrawal

Calculators A calculator will be necessary for this course. I strongly recommend the TI-83 or the TI- 84.

The Honor Code Quizzes, tests, and the final exam are pledged. On Excel assignments you may work with a partner.

Classroom Etiquette During a lecture, you are free to ask questions. It is polite to raise your hand first and wait to be called on. You should not talk to other students while I am talking. While working assigned problems in class, you are free to talk to other students provided you are talking about the assigned problems.

Classroom Etiquette Do not make leave the room during the class.  If necessary, use the bathroom before coming to class.  If you are thirsty, get a drink before class. Do not sleep in class. Do not work on assignments from other classes during class. Do not read the newspaper during class.

The Scientific Method Formulate a theory. Collect some data. Summarize the results. Make a decision.

The Scientific Method Formulate a theory – Chapter 1. Collect some data. Summarize the results. Make a decision.

The Scientific Method Formulate a theory – Chapter 1. Collect some data – Chapters 2 – 3. Summarize the results. Make a decision.

The Scientific Method Formulate a theory – Chapter 1. Collect some data – Chapters 2 – 3. Summarize the results – Chapters 4 – 5. Make a decision.

The Scientific Method Formulate a theory – Chapter 1. Collect some data – Chapters 2 – 3. Summarize the results – Chapters 4 – 5. Make a decision – Chapters 9 – 14.

The Scientific Method Formulate a theory – Chapter 1. Collect some data – Chapters 2 – 3. Summarize the results – Chapters 4 – 5. Make a decision – Chapters 9 – 14. Theoretical underpinnings – Chapters 6 – 8.

Formulate a Theory We are wondering whether a particular die is fair. If it is fair, then the numbers 1, 2, 3, 4, 5, and 6 should come up equally often. In particular, if we rolled the die 600 times, we expect to get each number 100 times.

Formulate a Theory Or do we?

Formulate a Theory The theory that the die is fair will be tested by posing it as a question with two competing answers. Question: Does the distribution of observed rolls match what we would expect to see if the die were fair?

Formulate a Theory The possible answers (yes and no) are stated more precisely as two competing hypotheses:  “Null hypothesis” The die is fair. Any deviations from the expected observation are due entirely to chance.  “Research hypothesis” The die is not fair. Any deviations from the expected observations are due to the bias in the die.

Collect Some Data So we roll the die 600 times and get the following results. Number Expected100 Observed

Two Possible Explanations There is a discrepancy. Can it be explained by chance?

Summarize the Results We use the TI-83 or TI-84, and compute a special quantity:  2 = 4.62.

Summarize the Results Use the TI-83 or TI-84, and compute a special quantity:  2 = If the die really is fair, then theory says that we expect this calculation to yield the value 5, plus or minus a bit.

Make a Decision Theory says that if the die is fair, then this value should be less than the critical value of Since  2 is less than the critical value, we conclude that the “null hypothesis” is correct: The die is fair.

An Important Question Does this procedure prove that the die is fair?

An Important Question Does this procedure prove that the die is fair? We may that it “proves” it statistically, but it does not prove it logically.