Predictive Analytics Software: What Statistics Can Do for You

Brett DeneckereDr. Kimberly Dodson

April 26, 2011A “Living Legend” Production

Why Do We Use Statistics In Research?

• To understand the professional literature,

• To understand the rational underlying research in the behavioral sciences, and

• To conduct behavioral science research:– Explaining, predicting, and controlling social behavior.– Tentative conclusions about the existence and strength of

social relationships.

What Are Statistics?• The recording, organizing, analyzing, and

reporting of quantitative information;

• A collection of numerical data that measure something; and

• Numerical tools used by researchers to help them describe and explain phenomena.

Descriptive Statistics• Descriptive statistics show the relationship

between variables.

• They are used to describe and summarize a particular data set.

Creating a Bar Graph How do you create

a graph? graph Well Doc, it’s actually not that hard. Let me

show you!

Select “Graphs” from the Menu

Select “Legacy Dialogs”

Select the “Bar Chart” Option

Select the “Simple” option

Click “Define”

Select a variable from the list.

Your selected variable appears here

Click OK and…

SHAZAM! Bar Graph

Testing RelationshipsWell Doc, that would depend on the level of measurement of

your variables!

What analysis would you use to find out if

two variables are related? graph

Variables• Variable type is important to determine the level of

measurement and the techniques available to analyze data.– Continuous• Can assume an infinite number of values– Examples: time, age, length

– Discrete• Can assume only a finite number of whole unit values– Examples: sex, political affiliation, number of children in a

family

Levels Of Measurement• Nominal– Variables can be placed in mutually exclusive,

exhaustive categories, but can’t be ordered any further. • Languages: English, Spanish, Chinese, Klingon

• Ordinal– Variables can be categorized as well as ranked

according to the degree to which a certain attribute is present• I love my mother: Strongly Agree, Agree, Neutral,

Disagree, Strongly Disagree

Levels Of Measurement• Interval– A scale with an arbitrary zero point, but equal

distance (intervals) between any two adjacent units.• Temperature in Celsius: 1°-100°

• Ratio– Contains all the properties of the first three levels,

but with an inclusion of an absolute zero point.• How much money is in your pocket: $4, $12, $20, $7,596

Can the data be ordered?

Is there a true zero?

Ratio

Are there equal intervals?

Interval

Ordinal

Nominal

YES

YES

YES

NO

NO

NO

Process for determining level of measurementAdapted from: Walker, J. (1999). Statistics in Criminal Justice. Gaithersburg, Maryland: Aspen.

Testing RelationshipsLet’s run a simple

crosstabs to answer that question!

graph

What if we wanted to examine the

relationship between gender

and tobacco use ?

Select “Analyze” from

the MenuSelect

“Descriptive Statistics”

Select the “Crosstabs” Option

Select the Variables you

want to Examine

Your Variables will Appear Here

Click “OK”

Hit “Continue” and…

Boom Boom Pow! A Crosstabulation

Crosstabs Results • The results indicate that males (54%) are more

likely than females (32%) to use tobacco. • Cramer’s V tells us the strength and direction

of the relationship between two nominal level variables.

• There is a weak positive relationship between gender and tobacco use with males reporting more use than females.

Testing RelationshipsLet’s run a simple

bivariate correlation to answer that

question!

graph

What if we wanted to know if gender is related to binge

drinking?

Bivariate Correlation • Bivariate correlation is a statistical technique

that gives us the strength and direction of a relationship between two variables.

Select “Analyze” from the menu

Select the “Correlate” option

Select the “Bivariate” option

Select your variables

Both of your variables will appear here

Click “OK” and…

WHOOPAH!A Bivariate Correlation

Chart

Bivariate Correlation Results • There is a weak positive relationship between

gender and binge drinking (r = .26, p = .01). • In other words, males are more likely to binge

drink than females.

Conclusions

Statistics are powerful!

Great Scott!

This is Heavy!