PHYS 2A - Data Analysis & Statistics Vocab

Vocabulary flashcards covering key statistical and data-analysis terms from the Physiology IIA research methods guide.

Population

The complete group of individuals or observations about which conclusions are desired (e.g., all people living in Adelaide).

Sample

A subset of the population selected for measurement and assumed to represent the population.

Random Sampling

Sampling method in which every population member has an equal chance of selection, helping ensure representativeness.

Mean

The arithmetic average of a data set; sum of all values divided by the number of values.

Mode

The value that appears most frequently in a data set.

Median

The middle value in an ordered data set, with half of the observations above and half below.

Normal (Gaussian) Distribution

Symmetrical bell-shaped distribution where values cluster around the mean; 68 % within ±1 SD, 95 % within ±2 SD, 99.7 % within ±3 SD.

Frequency Distribution Histogram

A graph showing how many observations fall into each interval (bin), used to visualise data distribution.

Standard Deviation (SD)

Measure of the spread or dispersion of data points around the mean in a sample.

Standard Error of the Mean (SEM)

Estimate of how far the sample mean is likely to be from the true population mean; calculated as SD ÷ √n.

Confidence Interval (CI)

Range around a statistic that likely contains the true population value; 95 % CI = mean ± 1.96 × SEM.

Descriptive Statistics

Numerical summaries that characterise data sets, such as mean, SD, SEM, and CI.

Null Hypothesis (H₀)

Statement that no effect or difference exists between the groups being compared.

Alternate Hypothesis (H₁)

Statement that an effect or difference does exist between the groups.

Alpha Level (α)

Pre-set threshold probability (commonly 0.05) for rejecting the null hypothesis; acceptable risk of a Type I error.

P-value

Probability of obtaining the observed result (or more extreme) if the null hypothesis is true; used to judge statistical significance.

Independent (Unpaired) t-test

Statistical test comparing the means of two separate, unrelated groups.

Paired t-test

Statistical test comparing means of two matched or repeated-measure groups (same subjects under two conditions).

One-Way ANOVA

Test assessing differences among three or more independent group means based on one factor.

Two-Way ANOVA

Analysis evaluating the effects of two independent factors and their interaction on one dependent variable.

Pearson’s Correlation

Measure of the linear relationship between two continuous variables.

Correlation Coefficient (r)

Value from −1 to +1 indicating direction and strength of a linear relationship.

Coefficient of Determination (R²)

Square of r; proportion of variance in one variable explained by the other.

Linear Regression

Method fitting a straight line (Y = mX + b) to model and predict the relationship between dependent and independent variables.

GraphPad Prism

Scientific software used to organise, analyse, and graph biomedical data, including descriptive stats, t-tests, and ANOVAs.

Statistical Power

Probability of correctly rejecting the null hypothesis when a true effect exists; often targeted at 80 %.

Type I Error

False positive; concluding a difference exists when it actually does not (rejecting a true null hypothesis).

Type II Error

False negative; failing to detect a true difference (not rejecting a false null hypothesis).