Holt Environmental Science Chapter 2

Experimental Method

A series of steps used across the world to identify and answer questions.

Observation

The process of obtaining information by using the senses. I.e: Sight, smell, taste, touch, and hearing.

Hypothesis

A testable idea or explanation that leads to scientific investigation.

Predictions

The expected outcome if a hypothesis is correct.

Experiment

A procedure designed to test a hypothesis or question under controlled conditions with controlled conditions.

Variable

Factor of interest; changes in accordance to the experiment.

Experimental Group

The group in an experiment that receives the variable being tested.

Control Group

The group in an experiment that does not receive the variable. Used to measure changes in the experimental group.

Data

Any pieces of information acquired through observation or experimentation.

Correlation

Association between two variables or events.

Statistics

The collection and classification of data that are in the form of numbers.

Statistical Population

A group of similar things that a scientist is interested in learning about.

Mean

The number obtained by adding up the data for a given characteristic and dividing this sum by the number of individuals.

Distribution

The relative arrangement of the members of a statistical population; usually shown as a graph.

Normal Distribution

Data is symmetrical around the mean on a graph; a bell-shaped curve.

Probability

The chance something will happen.

Sample

The group of individuals or events selected to represent a statistical population.

Sample Size

Number of events or objects sampled

Risk

The probability of an unwanted outcome.

Model

Representation of objects or systems.

Physical Model

A three-dimensional model you can touch.

Graphical Model

Any map or chart; visual models usually on a 2-D plane.

Conceptual Model

A verbal or graphical explanation for how a system works or is organized.

Mathematical Model

One or more equations that represent the way a system or process works.

Value

A principle or standard that an individual considers to be important.

Decision-Making Model

A conceptual model that provides a systematic process for making decisions.