Ap Stats Unit 1 Vocab

Important vocab

Statistics

Collecting and organizing data from samples to make assumptions of the populations

Statistical Study

A process of collecting data and making inferences from the data to answer questions.

Population

A large group of people or other things.

Sample

A subset of a population that is studied statistically.

Unit

A member of sample

Population Parameter

A number that describes population

Subject

A human unit

Observational Study

A study in which this person is observing characteristics or behaviors without trying to affect them

Experiment

A study in which the person conducting the study assigns units to different treatments and observes the effects of these treatments.

Variables:

Explanatory ( or Independent) Variable

The variable is adjustable

Response (or Dependent) Variable

The variable is measured

Cofounding (or lurking) Variable

A variable that is unaccounted for and has an effect on both explanatory and response variables

Control (control)

Accounting for confounding variables so you can infer changes in the response variable are due to the explanatory variable

Control group

The group that receives no special treatments

Control variable

A variable that is held constant in order to prevent it from becoming cofounding variable

Experimental Designs:

Completely Randomized Design

Units are designed for treatment at random and not group based on any characteristic

Randomized Block Design

Units with similar characteristics are grouped into blocks based on potential confounding variables, and units in each group are assigned to treatments at random

Matched Pairs Design

Units with similar characteristics are paired, and one unit in each pair is assigned to a treatment and the other is assigned to the control group

Blinding:

Double Blind Experiment

Not letting the subjects know their treatment group

AND not letting the observers know which treatment group the subjects are in

Single Blind Experiment:

EITHER not letting the subjects know their treatment group OR not letting the observers know which treatment group the subjects are in

Placebo

pill or medicine that has no effect

Correlation vs. Causation between two variables:

Correlation

A visible positive or negative trend between two variables (Example:

Shark attacks tend to increase as ice cream sales increase - positive correlation)

Causation:

Adjusting one variable causes changes in the other (Example: Taking a medicine speeds up recovery from a disease)

Miscellaneous Terms:

Replication

Being able to repeatedly receive consistent results in order to ensure the results are correct

Law of Large Numbers:

Repeating something many times makes experimental results closer to the expected results

Census:

Observing or surveying all people of a population