Part I Yippee! I’m in Statistics

1. Part IYippee! I’m in Statistics Chapter 1      Statistics or Sadistics?: It’s Up to You

2. Why Statistics? • Statistics for People Who (Think They) Hate Statistics • Follows an approach that is: • Un-intimidating • Informative • Applied • Even a little fun!

3. A Five-Minute History • 17th century the first set of data pertaining to populations was collected • Need arose to develop specific tools to help answer specific questions • Basic statistical procedures were developed in the fields of • Agriculture • Astronomy • Politics

4. Statistics: What It Is (and Isn’t) • Statistics describes “a set of tools and techniques that is used for describing, organizing, and interpreting data.” • The text will help you learn how to do the following with data: • Collect • Organize • Summarize • Interpret

5. Descriptive or Inferential? • What is Descriptive Statistics? • Used to organize and describe the characteristics of a particular data set • Example: the average age of everyone in this class! • What is Inferential Statistics? • Used to make inferences from your “sample” to the “population” • Example: comparing the mean age of students taking this course to average age of all students in an introductory statistics course

6. Why Statistics is Important • Understanding basic statistics will help you in the following ways: • Better prepare you for advance courses (both undergraduate or graduate) • Sets you apart from those who do not take courses in statistics • Challenges you intellectually • Makes you a better student in the behavioral or social sciences!!

7. Success in this Course • A few hints for successful completion of this course • You’re not dumb • How do you know statistics is hard? • Don’t skip lessons!! • Form a study group • Ask questions • Work through the exercises in each chapter • Practice, Practice, Practice • Look for real-world applications • Browse • HAVE FUN!!

8. About Those Icons

9. Key to Difficulty Index • VERY Hard  • Hard   • Not too hard, but not too easy    • Easy     • VERY Easy     

10. Glossary Terms to Know • Descriptive statistics • Data or data set • Inferential statistics • Population • Sample

11. Algebraic Order • Parentheses and Brackets -- Simplify the inside of parentheses and brackets before you deal with the exponent (if any) of the set of parentheses or remove the parentheses. • Exponents -- Simplify the exponent of a number or of a set of parentheses before you multiply, divide, add, or subtract it. • Multiplication and Division -- Simplify multiplication and division in the order that they appear from left to right. • Addition and Subtraction -- Simplify addition and subtraction in the order that they appear from left to right.

12. PEMDAS • Important:  It is not correct to say that we must always do addition before subtraction, because A comes before S in PEMDAS • For example:  4 - 1 + 7 - 2.  We get 8 working left to right • Another example:  5 x 6 ÷ 2 ÷ 5.  We get 3 working left to right.

13. Now You Try! • 2+5*X • 2+(3-1) * 32 • 5- (10)2 /50 • Sqrt [ 5(8) – (4)2 ] [ 3(6) –(3)2 ]

14. Learning a new languageTypes of variables • How it can be measured matters • Discrete variables • What is measured belongs to unique and separate categories • Pets: dog, cat, goldfish, rats • If there are only two categories, then it is called a dichotomous variable • Open or closed; male or female

15. Learning a new languageTypes of variables • Continuous variables • What is measured varies along a line scale and can have small or large units of measure • Length • Temperature • Age • Distance • Time

16. Learning a new languageMeasurement scales: Nominal • Measurement scales • Nominal scales • Separated into different categories • All categories are equal • Cats, dogs, rats • NOT: 1st, 2nd, 3rd • There is no magnitude within a category • One dog is not more dog than another.

17. Learning a new languageMeasurement scales: Nominal • No intermittent categories • No dog/cat or cat/fish categories • Membership in only one category, not both • Mutually exclusive properties

18. Learning a new languageMeasurement scales: Ordinal • Ordinal scales • What is measured is placed in groups by a ranking • 1st, 2nd, 3rd

19. Learning a new languageMeasurement scales: Ordinal • Although there is a ranking difference between the groups, the actual difference between the group may vary. • Marathon runners classified by finish order • The times for each group will be different • Top ten 4- to 5-hour times • Bottom ten 4- to 5-week times Time 1st place 2nd place 3rd place

20. Learning a new languageMeasurement scales: Interval • Interval scales • Someone or thing is measured on a scale in which interpretations can be made by knowing the resulting measure. • The difference between units of measure is consistent. • Height • Speed Length

21. Learning a new languageMeasurement scales • Ratio scale • Just like an interval scale, and there is a definable and reasonable zero point. • Time, weight, length • Seldom used in social sciences • All ratio scales are also interval scales, but not all interval scales are ratio scales -20 -10 0 +10 +20