Introduction to Statistics

Data Definition

Information from observations, counts, measurements, or responses.

Types of quantitative data:

Interval and Ratio

Types of qualitative data:

Nominal and Ordinal

4 ways to collect data:

Observation, Experiment, Surveys, and Simulations.

Ordinal

Qualitative and quantitative

Ratio

To find a ratio between two things. Including weight and time.

Interval

To find the mathematical difference. Including temperatures and dates.

Nominal

To list based on names.

Types of data:

To put in order (good, better, best).

Inferential Definition

Uses a sample to find conclusions, analyzations, and probability about a population.

Simulation

Using technology to simulate an actual event. Used when the event would be too dangerous or too expensive to do in real life.

Descriptive Definition

The organization, summarization, and display of data.

Parameter Definition

A number which describes a characteristic of a population.

Statistic Definition (in book)

A number which describes a characteristic of a sample.

Surveys

Ask a random sample of subjects well worded questions and record responses. Difficult to avoid bias.

Example of Experiment

At a college, ½ got laptops, ½ got paper for notes, the ones with paper did better on the test.

Why is a sample used more often than a population?

Because it is more difficult to get an accurate population where as a sample is smaller and easier to assess.

Why study statistics?

Data is everywhere.

Branches of Statistics

Descriptive and Inferential

Example of Observation

Doctors in the 50's noticed that there was a correlation between smoking and lung disease.

Experiment

Study where you impose a treatment and record the outcome and compare outcomes with a control group. Can show causation (may be difficult due to ethical/physical complications).

Observation

Study where you observe and record the outcome of a variable. Relatively easy to perform and can show correlation but not causation because of confounding variables.

Statistics Definition (from teacher)

The science of collecting, organizing, analyzing, and interpreting data.