LINDSEY BREWER

CSSCR (CENTER FOR SOCIAL SCIENCE COMPUTATION AND RESEARCH)

UNIVERSITY OF WASHINGTON

September 17, 2009

Introduction to SPSS(Version 16)

Topics we will cover today

SPSS at a glanceBasic Structure of SPSSCleaning your dataDescriptive StatisticsChartsData manipulationOther Resources

SPSS at a glance

SPSS stands for Statistical Package for the Social Sciences

SPSS was made to be easier to use then other statistical software like S-Plus, R, or SAS.

The newest version of SPSS is SPSS 17.0. Today we will be working on SPSS 16.0.

How to open SPSS

Go to START

Click on PROGRAMS

Click on SPSS INC

Click on SPSS 16.0

The computers in the CSSCR lab typically have SPSS on the desktop. It is a red box that says SPSS on the top.

Opening a data file

Click on FILE OPEN DATA

Click MY COMPUTER LOCAL DISK C:/

Click PROGRAM FILES SPSS

Click TUTORIAL SAMPLE FILES

Select CATALOG.SAV

Basic structure of SPSS

There are two different windows in SPSS

1st – Data Editor Window - shows data in two forms Data view Variable view

2nd – Output viewer Window – shows results of data analysis

*You must save the data editor window and output viewer window separately. Make sure to save both if you want to save your changes in data or analysis.*

Data view vs. Variable view

Data view Rows are cases Columns are variables

Variable view Rows define the variables

Name, Type, Width, Decimals, Label, Missing, etc. Scale – age, weight, income Nominal – categories that cannot be ranked (ID number) Ordinal – categories that can be ranked (level of

satisfaction)

Cleaning your data – missing data

There are two types of missing values in SPSS: system-missing and user-defined.

System-missing data is assigned by SPSS when a function cannot be performed.

For example, dividing a number by zero. SPSS indicates that a value is system-missing by one period in the data cell.

User-defined missing data are values that the researcher can tell SPSS to recognize as missing. For example, 9999 is a common user-defined missing value. To define a variable’s user-defined missing value…

Cleaning your data – missing data

Look at your variables in VARIABLE VIEWFind the column labeled MISSINGFind the variable that you would like to work with.Select that variable’s missing cell by clicking on the gray box in the right corner.click DISCRETE MISSING VALUESenter 9999 to define this variable’s missing value

A range can also be used if you only want to use half of a scale.

Cleaning your data – missing data cont.

When you have missing data in your data set, you can fill in the missing data with surrounding information so it does not affect your analysis.

click TRANSFORM click REPLACE MISSING

VALUES select the variable with

missing values and move it to the right using the arrow

SPSS will rename and create a new variable with your filled in data.

click METHOD to select what type of method you would like SPSS to use when replacing missing values.

click OK and view your new data in data view

Descriptive Statistics

Lets say we are interested in learning more about the number of customer service representatives (service).

Click ANALYZE

Click DESCRIPTIVE STATISTICS

Click FREQUENCIES

Choose service from the list.

Descriptive Statistics continued

Lets learn more about the number of catalogs mailed (mail).

Click ANALYZE

Click DESCRIPTIVE STATISTICS

Click DESCRIPTIVES

Move MAIL over with the arrow

Click OPTIONS – we can choose which statistics we are interested in looking at

We should remember that these descriptive statistics will not always make sense for every variable. For example, we should not be asking for the mean of nominal variables like gender or race.

Graphing Data

Click GRAPH

Click CHART BUILDER

Click HISTOGRAM

Put MEN on the X axis.

Click ELEMENT PROPERTIES. Check the box labeled DISPLAY NORMAL CURVE. This will impose a normal curve onto your graph. You can also change the style of your graph in this element properties window.

You can copy and paste these graphs into word and excel files.

Graphing Continued

There are other ways to make graphs.

Click ANALYZEClick DESCRIPTIVE

STATISTICSClick FREQUENCIESClick servicesClick CHARTClick BAR CHARTClick PERCENTAGES

By selecting cases, the researcher can select only certain cases for analysis

click DATAclick SELECT

CASESclick RANDOM

SAMPLE OF CASESselect your

preferences

Data manipulation – select cases

Data manipulation – compute new variable

Computing new variables – create a new variable from multiple variables

click TRANSFORM click COMPUTE fill in the new target variable

TOTALSALES fill in numeric expression =

men+women+jewel create an IF statement by

clicking on the IF button click INCLUDE IF CASE

SATISFIES CONDITION enter condition MAIL>10000 This new variable TOTALSALES tells us what the total sales

are for catalogs which mailed over 10,000 catalogs.

Data manipulation in action!

Try creating another variable for TOTALSALES2 for catalogs which mailed under 10,000 catalogs.

Try comparing the descriptive statistics of TOTALSALES and TOTALSALES2.

What did you find?

Recoding allows a researcher to create a new variable with a different set of parameters

click TRANSFORMclick RECODE INTO DIFFERENT VARIABLE

Data manipulation – recode a variable

move mail over to the right

create a name for the new variable mailcategories

click OLD AND NEW VALUES

click RANGE to create ranges of old values

click VALUE to create a new value for that range

Data manipulation – recode a variable cont.

Data manipulation in action!

Try recoding another variable on your own.

Try finding the descriptive statistics of your new variable.

Dummy variables is a variable that has a value of either 0 or 1 to show the absence or presence of some categorical effect

Data manipulation – create a dummy variable

To create a dummy variable…

click TRANSFORM click RECODE INTO

DIFFERENT VARIABLE

click OLD AND NEW VALUES

click RANGE to create range of old values

click VALUE to set new value to 0 or 1

What we have learned!

SPSS at a glanceBasic Structure of SPSSCleaning your data – missing dataDescriptive Statistics –

frequencies, descriptive statisticsChartsData manipulation – select cases,

recoding, dummy variables

Other Resources

There are many resources online to help you learn SPSS (tutorials, blogs, etc.)

CSSCR has a Quicktime SPSS class on its website

CSSCR offers SPSS handouts which are also on its website

CSSCR offers classes on SPSS each quarter – come back for the SPSS Beyond the Basics class!