Statistics chapter 2

Interval Width

The range of values contained in each interval of a grouped frequency distribution; also called class width

Interval

A discrete range of values within which the frequency of a subset of scores is contained

Ogive

A dot-and-line graph used to summarize the cumulative percent of continuous data at the upper boundary of each interval

Frequency Polygon

A dot-and-line graph used to summarize the frequency of continuous data at the midpoint of each interval

Pie Chart

A graphical display in the shape of a circle that is used to summarize the relative percent of discrete and categorical data into sectors

Histogram

A graphical display used to summarize the frequency of continuous data that are distributed in numeric intervals

Bar Graph

A graphical display used to summarize the frequency of discrete and categorical data that are distributed in whole units or classes; also called a bar graph

Bar chart

A graphical display used to summarize the frequency of discrete and categorical data that are distributed in whole units or classes; also called a bar graph

Stem-and-Leaf Display

A graphical display where each individual score from an original set of data is listed. The data are organized such that the common digits shared by all scores are listed to the left (in the stem), with the remaining digits for each score listed to the right (in the leaf); also called a stem-and-leaf plot

Stem-and-Leaf Plot

A graphical display where each individual score from an original set of data is listed. The data are organized such that the common digits shared by all scores are listed to the left (in the stem), with the remaining digits for each score listed to the right (in the leaf); also called a stem-and-leaf plot

Proportion

A part or portion of all measured data. The sum of all proportions for a distribution of data is 1.0

Grouped Data

A set of scores distributed into intervals, where the frequency of each score can fall into any given interval

Ungrouped Data

A set of scores or categories distributed individually, where the frequency for each individual score or category is counted

Simple Frequency Distribution

A summary display for (1) the frequency of each individual score or category (ungrouped data) in a distribution or (2) the frequency of scores falling within defined groups or intervals (grouped data) in a distribution

Frequency Distribution

A summary display for a distribution of data organized or summarized in terms of how often a category, score, or range of scores occurs

Relative Percent Distribution

A summary display that distributes the percentage of scores occurring in each class interval relative to all scores distributed

Relative Frequency Distribution

A summary display that distributes the proportion of scores occurring in each interval of a frequency distribution. It is computed as the frequency in each interval divided by the total number of frequencies recorded

Cumulative Frequency Distribution

A summary display that distributes the sum of frequencies across a series of intervals

Cumulative Relative Frequency Distribution

A summary display that distributes the sum of relative frequencies across a series of intervals. Relative frequencies can be added or cumulated from the bottom up or the top down in a frequency distribution

Cumulative Percent Distribution

A summary display that distributes the sum of relative percents across a series of intervals

Pictogram

A summary display that uses symbols or illustrations to represent a concept, an object, a place, or an event

Open Class

An interval with no defined upper or lower boundary; also called an open class

Open Interval

An interval with no defined upper or lower boundary; also called an open class

Outliers

Extreme scores that fall substantially above or below most of the scores in a particular data set

Real Range

One more than the difference between the largest value and the smallest value in a data set

Upper Boundary

The largest value in each interval of a grouped frequency distribution

Frequency

The number of times or how often a category, score, or range of scores occurs

Stem

The number(s) located to the left of the vertical line in a stem-and-leaf display. A stem lists the first digit or digits for each number in each row

Leaf

The number(s) located to the right of the vertical line in a stem-and-leaf display. A leaf lists the last digit or digits for each number in each row

Sector

The particular portion of a pie chart that represents the relative percentage of a particular class or category. To find the central angle for each sector, multiply each relative percent by 3.6

Percentile Rank

The percentage of scores with values that fall below a specified score in a distribution

Class Width

The range of values contained in each interval of a grouped frequency distribution; also called class width

Lower Boundary

The smallest value in each interval of a grouped frequency distribution

Interval Boundaries

The upper and lower limits for each interval in a grouped frequency distribution

Percentile Point

The value of a score on a measurement scale below which a specified percentage of scores in a distribution fall