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21 terms

Descriptive Statistics: Tabular and Graphical Presentations Chapter 2

Qualitative data

Labels of names used to identify categories of like items

Quantitative data

Numerical values that indicate how much or how many

Frequency distribution

A tabular summary of data showing the number (frequency) of items in each of several nonoverlapping classes

Relative frequency distribution

A tabular summary of datat showing the fraction or proportion of data itmes in each of the several nonoverlapping classies

Percent frequency distribution

A tabular summary of data showing the percentage of items in each of several nonoverlapping classes

Bar graph

A graphical deviace for depicting qualitative data that have been summarized in a frequency, relative frequency, or percent frequency distribution

Pie chart

A graphical device for presenting data summaries based on subdivision of a circle into sectors that correspond to the relative frequency for each class

Class midpoint

The value halfway between teh lower and upper class limits

Dot plot

A graphical device that summarizes datat by the number of dots above each data value on the horizontal axis

Histogram

A graphical presentation of a frequency distribution, relative frequency distibution, or percent frequency distribtuion of quantitative data constructed by placing the class intervals on the horizontal axis and the frequencies, relative frequencies, or percent frequencies on the vertical axis

Cumulative frequency distribution

A tabular summary of quantitative data showing the number of items with values less than or equal to the upper class limit of each class

Cumulative percent frequency distribution

A tabular summary of quantitative data showing the percentage of items with values less than or equal to the upper class limit of each classs

Ogive

A graph of cumulative distribution

Explotartory data analysis

Methods that use simple arithmetic and easy-to-draw graphs to summarize data quickly

Stem-and-leaf display

An exploratory data analysis technique that simultaneously rank orders quantitative data and provides insight about the shape of the distribution

Crosstabulation

A tabular summary of data for two variables. The classes for one varialbe are represented by the rows; the classes for the other variable are represented by the columns

Simpson's paradox

Conclusions drawn from two or more separate crosstabulations that can be reversed when the data are aggregated into a single cross tabulation

Scatter diagram

A graphical presentation of the relationship between two quantitative variables. One variable is shown on the horizontal axis and the other variable is shown on the vertical axis

Tendline

A line that provides an approximation fo the relationship between two variables

Formula for Relative Frquency

(Frequencyoftheclass) / n

Formula for Approximate Class Width

(Largest data value - Smallest data value) / Number of classes