Statistics

1. Statistics Spring 2008

2. Introduction • Dr. Robb T. Koether • Office: Bagby 114 • Office phone: 223-6207 • Home phone: 392-8604 (before 11:00 p.m.) • Office hours: 2:30-4:00 MWRF, 3:30 – 4:00 T • Other hours by appointment • E-mail: rkoether@hsc.edu • Web page: http://people.hsc.edu/faculty-staff/robbk Introduction

3. The Course • The class meets in Bagby 022 at 8:30 - 9:20 MWF and at 2:30 – 3:20 T. • The text for the course is Interactive Statistics, 3rd ed., by Martha Aliaga and Brenda Gunderson. • The web page for this course is at http://people2.hsc.edu/faculty-staff/robbk/Math121 Introduction

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

5. Grading • There will be • Weekly quizzes • Three tests • A final exam Introduction

6. Grading • In the final average, these will have the following weights: Introduction

7. 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. Introduction

8. 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. Introduction

9. Homework • At the beginning of each class meeting (except on Tuesdays), 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. Introduction

10. Quizzes • Each Tuesday 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. Introduction

11. Tests • The test schedule is as follows: Introduction

12. 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. Introduction

13. 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 Introduction

14. Attendance • Sending me an e-mail or leaving me a voice message does not excuse you from class. Introduction

15. Attendance • When assigning final grades, attendance will be taken into account. Introduction

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

17. The Honor Code • Quizzes, tests, and the final exam are pledged. Introduction

18. 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. Introduction

19. 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. Introduction

20. Goals of this Course • To learn statistics. • The theoretical basis of the statistical method. • How to perform statistical tests. • How to interpret statistics. • To become a more sophisticated thinker. • To become a more sophisticated consumer of information. Introduction

21. Goals of this Course • To get you through your freshman year with a decent GPA. Introduction

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

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

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

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

26. 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. Introduction

27. 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. Introduction

28. Formulate a Theory • We are wondering about the distribution fo colors in bags of milk chocolate M&Ms. • The manufacturers state that the distribution is • Blue – 24% Yellow – 14% • Orange – 20% Brown – 13% • Green – 16% Red – 13% Introduction

29. The Expectation • If we buy a bag of 53 milk chocolate M&Ms, how many of each color do we expect to see? • 24% of 53 = 12.72 14% of 53 = 7.42 • 20% of 53 = 10.60 13% of 53 = 6.89 • 16% of 53 = 8.48 13% of 53 = 6.89 Introduction

30. Formulate a Theory • Do we really expect to see that many of each color? Introduction

31. Formulate a Theory • The theory that the distribution agrees with the company’s statement will be tested by posing it as a question with two competing answers. • Question: Does the distribution of observed colors agree with what we would expect to see if the company’s claim is correct? Introduction

32. Formulate a Theory • The possible answers (yes and no) are stated more precisely as two competing hypotheses: • Null hypothesis: The company’s claim is correct. • Research hypothesis: The company’s claim is not correct. Introduction

33. Collect Some Data • We count our colors and get the following results. Introduction

34. Two Possible Explanations • There is a discrepancy. • Can it be explained by chance? • If yes, then chance is the explanation. • If no, then the explanation is that the company’s claim is wrong. Introduction

35. Allowance for Randomness • We will calculate a single number that measures how large the discrepancy is. • If this number is not too large, then the discrepancy can be explained by chance. • How large is too large? Introduction

36. Allowance for Randomness Distribution of Expected Values Introduction

37. Summarize the Results • We use the TI-83 or TI-84, and compute the value 5.19. Introduction

38. Allowance for Randomness Just about in the middle! Distribution of Expected Values Introduction

39. Make a Decision • Since this value is well within the expected range, there is no reason to doubt the null hypothesis. • We conclude that the company’s claim is correct. Introduction

40. An Important Question • Does this procedure prove that the company’s claim is correct? Introduction