Chapter 2 data set

Frequency Distribution

An organized tabulation showing how many individuals are located in each category on the scale of measurement.

Descriptive Statistical Techniques

Methods used to organize and simplify data to provide an overview of the results.

Grouped Frequency Distribution

A frequency distribution where the X column lists groups of scores, called class intervals, instead of individual values.

Histogram

A graph with bars representing frequencies for scores or class intervals, where adjacent bars touch.

Polygon

A graph where dots are centered above each score representing frequency, connected by a continuous line.

Bar Graph

A graph for nominal or ordinal data, featuring spaces between bars to illustrate separate categories.

Relative Frequency

The proportion of individuals in each category calculated as f/N, often used when exact counts are not known.

Smooth Curve

A graphical representation of population distributions on an interval or ratio scale, emphasizing the distribution's overall shape rather than exact frequencies.

Central Tendency

A statistical measure that defines the center of a distribution, typically using the mean, median, or mode.

Skewed Distribution

A distribution where scores tend to pile up toward one end of the scale, creating a tail on the opposite end.

Bimodal Distribution

A distribution with two modes.

Multimodal Distribution

A distribution with more than two modes.

Mean

The balance point of a distribution, calculated as the sum of scores divided by the number of scores.

Median

The midpoint of a distribution, dividing the ordered list into two equal halves.

Mode

The score or category that occurs most frequently in a distribution.

Positively Skewed Distribution

A distribution where scores pile up on the left side, with the tail extending to the right.

Negatively Skewed Distribution

A distribution where scores pile up on the right side, with the tail extending to the left.

Stem-and-Leaf Display

A method that divides scores into stems and leaves to efficiently represent a frequency distribution.

Weighted Mean

An average that takes into account the different sizes of samples when combining data.

Open-ended Distribution

A distribution where there is no upper or lower limit for one of the categories, complicating the computation of means.