Stats 4400 Chapter 3

Arithmetic mean

the sum of a set of scores in a distribution, divided by the total number of scores summed; also called an arithmetic mean or average.

Average

the sum of a set of scores in a distribution, divided by the total number of scores summed; also called an arithmetic mean or average.

Bell-shaped distribution

the sum of a set of scores in a distribution, divided by the total number of scores summed; also called an arithmetic mean or average.

Gaussian distribution

the sum of a set of scores in a distribution, divided by the total number of scores summed; also called an arithmetic mean or average.

Mean

the sum of a set of scores in a distribution, divided by the total number of scores summed; also called an arithmetic mean or average.

Normal distribution

the sum of a set of scores in a distribution, divided by the total number of scores summed; also called an arithmetic mean or average.

Sample mean

the sum of a set of scores in a sample, divided by the total number of scores summed.

Mode

the value in a data set that occurs most often or most frequently.

Negatively skewed

a distribution of scores in which a few outliers are substantially smaller (toward the left tail in a graph) than most other scores.

Multimodal distribution

a distribution of scores in which more than two scores occur most often or most frequently. A multimodal distribution has more than two modes.

Modal distribution

a distribution of scores in which one or more scores occur most often or most frequently.

Bimodal distribution

a distribution of scores in which two scores occur most often or most frequently. A bimodal distribution has two modes.

Skewed distribution

a distribution of scores that includes outliers or scores that fall substantially above or below most other scores in a data set.

Positively skewed

a distribution of scores where a few outliers are substantially larger (toward the right tail in a graph) than most other scores.

Nonmodal distribution

a distribution of scores with no mode; hence, all scores occur at the same frequency; also called a rectangular distribution.

Rectangular distribution

a distribution of scores with no mode; hence, all scores occur at the same frequency; also called a rectangular distribution.

Unimodal distribution

a distribution of scores, where one score occurs most often or most frequently. A unimodal distribution has one mode.

Symmetrical distribution

a theoretical distribution with data that are symmetrically distributed around the mean, median, and mode; also called a symmetrical, Gaussian, or bell-shaped distribution.

Median

the middle value in a distribution of data listed in numeric order.

Sample size (n)

the number of individuals that constitute a subset of those selected from a larger population.

Population size (N)

the number of individuals that constitute an entire group or population.

Population mean

the sum of a set of scores in a population, divided by the total number of scores summed.

Central tendency

statistical measures for locating a single score that is most representative or descriptive of all scores in a distribution. Examples include the mean, the median, and the mode.

Weighted mean

the combined mean of two or more groups of scores, where the number of scores in each group is disproportionate or unequal.