Statistics: Distribution Characteristics, Normal Distributions, and Formulas

Vocabulary flashcards defining fundamental statistics concepts related to distribution types, skewness, z-scores, and key formulas.

Distribution

The way data values are spread out or arranged

Skewness

A measure of the asymmetry indicating how "off-center" the data is

Modality

The number of prominent peaks in a distribution graph

Tail of a distribution

The tapered section on either end of a distribution that represents values far away from the central peak

Bell curve

A graph with a symmetrical shape that rises to a peak in the center and tapers off on both sides

Z-Score

A number that shows how many standard deviations a value is above or below the mean

Z-Score Chart

A chart that shows the area to the left of a z-score in the standard normal distribution

Symmetric Distribution

When the data values are evenly distributed about the mean

Skewed Distribution

When the data values are not evenly spread around the mean

Unimodal Distribution

A distribution with one clear peak

Multimodal Distribution

A distribution with more than one clear peak

Uniform Distribution

When the data values are equally spread over the range of possible values

Negatively (Left) Skewed Distribution

When the majority of the data values fall to the right of the mean

Positively (Right) Skewed Distribution

When the majority of the data values fall to the left of the mean

Normal Distribution

A continuous, symmetric, bell-shaped distribution of a variable

Standard Normal Distribution

A normal distribution with a mean of $0$ and a standard deviation of $1$

Non-Standard Normal Distribution

A normal distribution with any mean and any standard deviation

Skewness Formula

$$S = \frac{3(\text{mean} - \text{median})}{\text{standard deviation}}$$

Z-Score Formula

$$Z = \frac{\text{value} - \text{mean}}{\text{standard deviation}}$$