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