HW: Read article at http://abcnews.go.com/Technology/story?id=6034371&page=1#.T-NzPfWlidw8/20

Handouts:

Chapter P – Key Concepts

**Statistics** – the science and art of collecting, organizing, describing, and drawing conclusions from data. Involves *data production, data analysis, probability, and statistical inference*

**Data-** numbers within a context (100 does not mean anything until you put the “$” in front of it)

**Data production**- helps answer specific questions with an experiment or observational study

**Population** – a large group

**Sample-** a smaller, subgroup that represents the population

**Probability** – the study of chance behavior, tells you how likely or unlikely an event is to occur. **Chance behavior is unpredictable in the short run by has a regular and predictable pattern in the long run**

**Available data – **data that was produced in the past for some other purpose but that may be helpful to answer a present question

**Survey**- a popular way to gauge public opinion

**Observational study** – observe individuals and measure variables of interest but do not attempt to influence the responses

**Experiment** – deliberately do something to individuals in order to observe their responses

**Data analysis –** organizing, displaying, summarizing, and asking questions about the data

**Individuals**- the objects described by a set of data. Individuals may be people, animals, or things

**Variable-**any characteristic of an individual

**Categorical variable**- places an individual into one several groups or categories (gender, grade level)

**Quantitative variable** – takes numerical values for which arithmetic operations such as adding and averaging make sense (SAT score, salary)

**Distribution** – tells us what values the variable takes and how often it takes these values

***Many relationships between two variables are influenced by other variables lurking in the background **

**Exploratory data analysis**- uses graphs and numerical summarizes to describe the variables in a data set and the relationships among them. May not be generalizable beyond the specific data studied

**Statistical inference**- produces answers to specific questions, along with a statement of how confident we can be that the answer is correct. Usually intended to apply beyond the individuals specifically studied.