Mastering ACT Science: Critical Thinking and Data Analysis

Independent Variable (IV)

The variable the scientist changes or manipulates in an experiment.

Dependent Variable (DV)

The variable being measured or observed in response to the independent variable.

Controlled Variables (Constants)

Factors kept the same across all trials to ensure valid results.

Control Group

A baseline group that receives no treatment or a standard treatment for comparison.

Validity

The degree to which an experiment accurately tests the hypothesis and produces reproducible results.

Sample Size

The number of subjects or observations in a study; larger samples provide more reliable results.

Confounding Variables

External factors not controlled in an experiment that may affect the results.

Duration

The length of time an experiment runs; must be appropriate to observe trends.

Direct Relationship

A relationship where as one variable increases, the other also increases.

Inverse Relationship

A relationship where as one variable increases, the other decreases.

No Relationship

A situation where changes in one variable have no consistent effect on another variable.

Correlation

A statistical association between two variables without implying causation.

Causation

A relationship where one variable directly affects another.

Interpolation

Predicting a value within the range of measured data points.

Extrapolation

Predicting a value outside the measured range of data.

Trend

A general direction or pattern in data, often seen in graphs.

Mechanism

The process or method by which a particular effect occurs.

Data Focus

The specific data that a scientist emphasizes in an argument or hypothesis.

Conflict (in hypotheses)

Where two or more hypotheses disagree on the explanation of a phenomenon.

Claim (in hypothesis)

The statement or assertion made by a hypothesis.

Yes/No, Because… Pattern

A logical structure often used in answer choices to support a hypothesis.

Over-Extrapolation

Assuming a trend continues indefinitely without considering biological limits.

Misinterpreting 'supported by'

Confusing a hypothesis being supported by data as being proven completely correct.

DRY MIX

A memory aid for experimental design: Dependent Responding Y-axis, Manipulated Independent X-axis.

Evaluation of Experimental Models

Using a comparative strategy to assess competing scientific hypotheses.

Fighting Scientists

A term used to describe the conflicting viewpoints passage on the ACT Science test.

Graph Types

Different styles of data representation, including direct, inverse, and complex relationships.