Chapter 4 A Picture is Really Worth a Thousand

Words

Part IISigma Freud & Descriptive

Statistics

Why Illustrate Data?

When describing a set of scores you will want to use two things…One score for describing the group of data

Measure of Central TendencyMeasure of how diverse or different the

scores are from one anotherMeasure of Variability

However, a visual representation of these two measures is much more effective when examining distributions.

Ten Ways to a Great Figure

Minimize the “junk”Plan before you start creatingSay what you mean…mean what you sayLabel everythingCommunicate ONE ideaKeep things balancedMaintain the scale in the graphRemember…simple is bestLimit the number of wordsThe chart alone should convey what you

want to say

Frequency Distributions

Method of tallying, and representing the number of times a certain score occursGroup scores into interval classes/ranges

Creating class intervalsRange of 2, 5, 10, or 20 is usually good10-20 class intervals for the entire range of

dataDivide total # of data points by # of class

intervals desired to determine numeric range of the class intervals

HistogramsHand Drawn Histogram

HistogramTally-Ho Method

Frequency PolygonA “continuous line that represents the

frequencies of scores within a class interval”

Cumulative Frequency Distribution

Fat & Skinny of Frequency Distributions

Distributions can be different in four different ways…Average valueVariabilitySkewnessKurtosis

Average Value

Variability

SkewnessPositive & Negative Skewness

KurtosisPlatykurtic (A) & Leptokurtic (C)

Cool Ways to Chart DataColumn Chart

Cool Ways to Chart DataLine Chart

Cool Ways to Chart DataPie Chart

Using the Computer to Illustrate Data

Creating Histogram Graphs

Using the Computer to Illustrate Data

Creating Bar Graphs

Using the Computer to Illustrate Data

Creating Line Graphs

Using the Computer to Illustrate Data

Creating Pie Graphs