Visualizing Data - Psyc2320

Flashcards covering key vocabulary related to data visualization and distributions based on the Psyc2320 lecture notes by Dr. Eidson.

Distributions of Data

How often scores/values occur in data (frequency), characterized by both spread (x-axis) and differences in frequency (y-axis).

Frequency Distribution

A collection of observations produced by sorting observations into classes and showing their frequency (f) of occurrence in each class.

Ungrouped Frequency Distribution

A type of frequency distribution where each class contains only one value. It is typically used with less than 20 values.

Grouped Frequency Distribution

A type of frequency distribution where classes contain more than one value, requiring observations to fall into one and only one class, and displayed with lowest values at the bottom.

Class Overlap (Frequency Distribution Guideline)

Classes in a frequency distribution should not overlap (e.g., instead of 45-50, 50-55, use 45-49, 50-54).

Class Width (Frequency Distribution Guideline)

All classes in a frequency distribution must be equal in width, have upper and lower boundaries, and their lower boundary should be a multiple of the class width.

Data Range

The difference between the largest and smallest observation in a dataset.

Class Width Formula

Calculated by dividing the data range by the desired number of classes (usually 10), then rounded off to the nearest convenient width.

Relative Frequency

Shows the frequency of each class as a part or fraction of the total frequency for the entire distribution (frequency per class / total frequency).

Cumulative Frequency

Shows the total number of observations in each class and all lower-ranking classes.

Percentile Rank

The percentage of scores in the entire distribution with similar or smaller values than a given score.

Bar Graph

A data representation used for discrete, nominal data where the bars do not touch.

Histogram

A data representation used for discrete, ordinal, or nominal data where the bars touch and the order of data matters. It can be created from frequency distributions.

Frequency Polygon

A data representation used for continuous, ordinal data where points are connected by lines, including estimated points between actual data points.

Modality (of a distribution)

Refers to the number of peaks in a distribution.

Skewness (of a distribution)

Refers to whether a distribution is symmetric or asymmetric.

Normal Distribution

A symmetric, often bell-shaped distribution, representing a fundamental concept in statistics.