AP Biology: Biology Review, Intro to Stats, and Water

Scientific Method

a step-by-step process used by scientists to investigate questions, gather evidence, and draw conclusions based on experiments and observations

Hypothesis

a testable explanation form an observation; explains relationship between variables and what the researcher expects to happen to one variable if the other changes

Null Hypothesis

hypothesis that there is no effect or no difference between the two groups of data; observations are due to chance

Alternative Hypothesis

Hypothesis that there IS a relationship/effect/ difference between the two groups of data; observations are due to a nonrandom cause

Control

used for comparison to teh experimental group; helps to validate statistical analysis and increase confidence in conclusions drawn from teh experimental results

Negative vs Positive Control

Negative: group not exposed to any treatment OR exposed to a treatment known to have no effect

Positive: group not exposed to the IV but IS exposed to a treatment known to have an expected effect

Independent Variable

the one factor that is changed between groups; what is being manipulated; graphed on the X axis

Dependent Variable

Factor that is measured and affected by the IV; graphed on the Y axis

Constant

factors kept consistent for all groups to ensure only the IV affects the outcome; aka controlled variables