1. Vocabulary of Statistics
Part One

2. Stastistics
Original word came from:
State Arithmetic

3. Variable
A characteristic or attribute that can assume different values.
example: What color shoes are you wearing?
example: How many times a week do you eat fruit?

4. Data
The values (measurements or observations) that the variables can assume.
Example: I am wearing a green shirt.
Example: 4 times a week I eat an apple.

5. Random variables Where value is determined by chance
Example: Rolling a pair of dice.
Example: Flipping a coin.

6. Example
Suppose that an insurance company studies its records over the past several years and determines that, on average, 3 out of every 100 automobiles the company insures were involved in an accident during a 1-year period.
What is the variable?
What is the data?
Is the data random?

7. Data Set A collection of data values.
Each individual value is called a data value or a datum

8. Data can be used in different ways
Data can be used in different ways. The body of knowledge called statistics is sometimes divided into two main areas, depending on how the data are used. The two areas are: Descriptive statistics Inferential statistics

9. Descriptive Statistics
Used to describe a situation.
U.S. Census – average age, income, number of children, etc.

10. Descriptive Statistics
Consists of the collection, organization, summarization, and presentation of data.

11. Inferential Statistics
Use of a sample to infer (predict) the particulars of a population.
Inferential statistics use probability – the chance of an event occuring.
Probability theory is used in areas like gaming and insurance.

12. Population: Consists of all subjects (human or otherwise) that are being studied.
Sample: A group of subjects selected from a population.

14. Inferential Statistics
Consists of generalizing from samples to populations, performing estimations and hypothesis tests, determining relationships among variables, and making predictions.

15. Inferential Statistics
If the subjects of a sample are properly selected, most of the time they should possess the same or similar characteristics as the subjects of the population.
Your assignment: Write a paragraph explaining how you would take a random sample of people who live in Pittsylvania county. Keep in mind; you need to devise a method that will not be biased in any way.