Scientific Method and Statistics Vocabulary

A complete set of vocabulary flashcards based on the provided lecture notes covering scientific experimentation, data visualization, and statistical concepts.

Alternative hypothesis

A statement predicting that there is a relationship or difference between variables in an experiment.

Bar graph

A graph that uses separate bars to compare different categories of data.

Box & whisker plot

A graph that shows the distribution of data, including the median, quartiles, and possible outliers.

CER

Claim, Evidence, Reasoning: a method for explaining a scientific conclusion using evidence and connecting it to scientific principles.

Cell

The smallest unit of life that can carry out all basic functions necessary for life.

Chi-square ($\chi^2$)

A statistical test used to determine whether the difference between observed and expected results is likely due to chance.

Controlled experiment

An experiment where one variable is deliberately changed while other conditions are kept constant to determine its effect.

Controlled variable/constant

A factor that is kept the same throughout an experiment.

Control group

The group in an experiment that does not receive the experimental treatment and is used for comparison.

Critical value

A cutoff value used to determine whether a statistical result is statistically significant.

Data table

An organized display of data using rows and columns.

Degrees of freedom (df)

The number of values in a statistical calculation that are free to vary; for chi-square, it is usually number of categories $- 1$.

Dependent variable

The variable that is measured or observed in an experiment; it changes in response to the independent variable.

DNA

Deoxyribonucleic acid, the molecule that stores and transmits genetic information in cells.

Error bars ($2 \pm \text{SEM}$)

Lines on a graph showing the uncertainty or variation around a measured value. $2 \pm \text{SEM}$ means the mean is displayed with two standard errors of the mean above and below it.

Evolution

The change in inherited characteristics of populations over generations.

Experimental group

The group that receives the treatment or change being tested.

Hypothesis

A testable explanation or prediction about how variables are related.

Independent variable

The variable that the researcher deliberately changes or manipulates.

Law

A scientific statement that describes a consistent pattern or relationship in nature, often supported by repeated observations.

Line graph

A graph that shows how one variable changes in relation to another, often over time.

Line of best fit

A line drawn through a scatter plot that represents the overall trend in the data.

Mean

The average of a set of numbers. Add all values and divide by the number of values.

Median

The middle value when data are arranged from smallest to largest.

Mode

The value that occurs most frequently in a data set.

Negative control

A control group that is not expected to produce the experimental effect, helping show that any observed effect is caused by the experimental variable.

Null hypothesis ($H_0$)

A statement that there is no significant relationship or difference between the variables being tested.

P-value

The probability of getting results at least as extreme as the observed results if the null hypothesis is true. A small p-value suggests the result is unlikely to be due to chance.

Positive control

A control that is expected to produce a known effect, showing that the experiment is capable of detecting that effect.

Qualitative data

Descriptive, non-numerical observations, such as color, texture, or behavior.

Quantitative data

Data expressed as numbers or measurements, such as height, mass, or temperature.

Rate

The change in one quantity over a specific amount of another quantity, often written as a change per unit of time.

Scatter plot

A graph that displays individual data points to show the relationship between two quantitative variables.

Standard deviation (SD)

A measure of how spread out data values are from the mean. A larger SD means greater variation.

Standard error of the mean (SEM)

A measure of how precisely a sample mean estimates the population mean. Smaller SEM generally means greater precision.

Statistical significance

A result that is unlikely to have occurred simply because of random chance, based on a chosen significance level.

Statistics

The collection and analysis of data to describe patterns and determine whether results are meaningful.

Theory

A well-supported scientific explanation of natural phenomena that is backed by extensive evidence.

Trial

A single repetition or run of an experiment.

Variable

Any factor in an experiment that can change or have different values.

X-axis

The horizontal axis of a graph. It usually represents the independent variable.

Y-axis

The vertical axis of a graph. It usually represents the dependent variable.