Biological Science - How to Experiment

Scientific Method Steps

1. Observe 2. Hypothesize 3. Experiment 4. Analyze 5. Conclude.

Hypothesis

An idea about a question/problem that has not been tested much or at all.

Theory

A hypothesis that has been extensively tested and is backed by evidence.

Independent Variable

The variable that changes in an experiment, often referred to as the manipulated variable.

Dependent Variable

The variable that is measured during an experiment.

Controlled Experiment

An experiment that includes a part where a normal version of the thing being tested is not affected by the independent variable.

Normal Curve

A typical representation of statistical information showing the mean in the middle with three standard deviations on either side.

68/95/99 Rule

68% of data is within 1 standard deviation, 95% is within 2 standard deviations, and 99% is within 3 standard deviations.

Alpha

The significance threshold for comparing results, typically set at .05.

T-test

A statistical test that compares means between two groups.

T Value Formula

T = (mean 1 - mean 2) / 1 standard deviation.

Critical Value

The value that indicates the rejection region for the null hypothesis, demonstrating a relationship between variables.