biometrics notes (2)

module two

Descriptive Statistics

Statistics that focus on summarizing and presenting data effectively.

Qualitative Data

Data that includes nominal and ordinal variables, showing relative proportions in various categories.

Circle Graph (Pie Chart)

A graph that shows the relative proportions of different categories, must include a title and legend.

Bar Graph

A graph displaying frequencies or relative frequencies using bars, must have title, labeled axes, and clear categories.

Frequency vs. Relative Frequency

Frequency is the actual count of occurrences, while relative frequency is the proportion (%) of occurrences in a dataset.

Quantitative Data

Numerical data that can be discrete (specific values) or continuous (range of values).

Stem and Leaf Diagram

A graph that retains original data values while showing the distribution.

Frequency Distribution

A table showing values (x) and their frequencies (y), where bars must touch.

Frequency Histogram

A graph that displays grouped data with touching bars.

Measures of Central Tendency

Statistics that describe the center of a dataset: mean, median, and mode.

Mean

Arithmetic average calculated by adding all values and dividing by the number of observations.

Median

The middle value of a dataset; calculated differently for odd and even number of observations.

Mode

The most frequent value in a dataset, which can be bimodal or multimodal.

Range

The difference between the maximum and minimum values in a dataset.

Variance (s²)

A measure of the average squared deviation from the mean.

Standard Deviation (s)

The square root of variance, expressing the spread of data in the same unit as the data.

Percentiles

Values below which a certain percentage of data falls.

Quartiles

Values that divide the dataset into four equal parts.

Box-and-Whisker Plot

A graph that visualizes minimum, Q1, median (Q2), Q3, and maximum, showing outliers and spread.

Skewed Distribution

A representation of data where it is not symmetrical, indicating a skew in the mean, median, and mode.

Correlation ≠ Causation

The principle stating that correlation between two variables does not imply that one causes the other.

Misleading Graphs

Graphs that distort information through techniques like truncation, 3D effects, or axis mislabeling.

Open Access to Research

Requirement for taxpayer-funded research to be freely available to the public.