What is Statistics?

Art and Science of dealing with data. Data: numbers with a context (units)…

makes it informative. Context engages our background

knowledge and allows us to make judgments about the significance of the number.

Uses data to gain insight and draw conclusions.

Sports Healthcare professionals. Public policy, and many different fields of

study. Managers (efficient crunching of numbers

results in a better bottom line). Scientists/Engineers This list could go on and on

1. Producing Data

2. Organizing and Describing Data

3. Chance

4. Inference

Describes methods for producing data which can give clear answers to specific questions.

Where the data comes from is important…

Learn how to select samples and design.

Experiments are very influential in statistics.

Example – Opinion polls, clinical trials, etc…

Methods and strategies for exploring, organizing and describing data.

Using graphs and numerical summaries.

Learn how to look at data intelligently.

Probability

Variation

Risk

Moves beyond the data to draw conclusions.

Take into account that variation is everywhere

Conclusions can be uncertain.

When we talk about data, a big part of stats is deciding what to measure in order to produce data that helps answer your questions.

Need a clear objective before collecting data.

Measurements are made on individuals and organized in variables.

What do these number mean to you?

The birth weights of my kids

The mean nothing without units

9.6 pounds and 9.0 pounds

Individuals – the objects described by a set of data

Ex – people, animals, things Variable – any characteristic of an individual

Can take different values for different individuals.

Although Statistics deals with numbers. Not all variables are numerical.

To use Statistics with other (non-numerical) variables we use counts or percents.

Quantitative variables – numerical values (you can perform any type of arithmetic with these)

Ex – test scores, age, salaries, etc…

Categorical variables – use percents or counts; places an individual into one or several groups or categories

Ex – grade level, class, eye color

Individuals - ◦Students in class

Variables – 1. ID (categorical)2. Grade Level (categorical, not

numerical…Fresh, Soph, Junior, Senior OR 9, 10, 11, 12)

3. Gender (categorical)4. HR (categorical)5. Counselor (categorical)6. Test 1 (numerical/quantitative)

1. Textbook: Pgs. 7&8 #1-4

2. Data collection sheet

3. Celtics examples