AN INTRODUCTION TO SPSS www.danielboduszek.com [email protected] Daniel Boduszek University of Huddersfield
AN INTRODUCTION TO
SPSS
www.danielboduszek.com [email protected]
Daniel Boduszek University of Huddersfield
Outline
Beginning SPSS session
Defining the variables
Entering and modifying data
Useful SPSS features
Screening & cleaning the data
Beginning SPSS session
Click on the SPSS shortcut button on your desktop. OR
Go to START, click on All PROGRAMS, and click on SPSS
Basics
Toolbar: contains icons to facilitate easy point and click operations
Open files Undo last operation
Save data Redo last operation
Print file Insert case
Find data Insert variable
Basics
Menu Bar: provides a series of “drop down” commands to perform most essential SPSS functions.
File: These are the basic file management operations.
e.g. opening, saving, and printing files
Edit: This allows you to perform editing functions on the current data set.
e.g. cut, copy, clear, undo changes and redo changes
View: Allows you to change the current view of data, as well as toolbar options.
e.g. grid lines, value labels
Data: These functions deal with the configuration, defining, and management of data.
e.g. insert variables/cases, sort data, merge files
Transform: This allows you to transform the data set you’ve entered.
e.g. calculating new variables, recoding, missing values
Analyze: Includes the main data analysis functions.
e.g. descriptive statistics, t-Tests, ANOVA, correlation
Defining the variables
Variable View – define your variables
Data View - enter your raw data
Procedure for defining variables
Click on Variable View
Each row represents a different variable that you will use in your analysis.
At the very least you need to enter a name for each variable
SPSS limits you to a name between 1-8 characters long.
Procedure for defining variables
TYPE
The default is numeric data.
The most common format change is to “string” data, which will allow you to enter words rather than numbers.
Procedure for defining variables
Width
This allows you to set the maximum number of digits (or letters in a string format) you can enter in cell.
The decimal and all decimal points count as digits in the width.
Procedure for defining variables
DECIMALS
This indicates how many decimal points you can have in your cell.
Procedure for defining variables
LABEL
Because the variable name can only be 8 characters long, you can enter a longer description of the variable here.
Procedure for defining variables
Values – define the meaning of the values you have used to code your variables
Click on the 3 dots on the right-hand side of the cell. This opens Value Label box
Click in box Value. Type in 1.
In Label box tape “NonV” (Non-violent offenders)
Click on Add
Repeat for Violent offenders
Click OK
Procedure for defining variables
Missing – missing value (-9)
Columns – set at 8
Align – set at Right
Procedure for defining variables
Measure – level of measurement Scale (interval or ratio)
Nominal (categorical)
Ordinal (ranking data)
Entering Data
Click on Data View tab at the bottom left hand side of the SPSS window
A spreadsheet should appear with your defined variable names listed across the top
Click on the first cell of the data set and type in the number (value)
Participants
Modifying the data file
Delete a case – move down to the case (row) and press Delete button
Insert a case between existing cases – move cursor to a cell (row) immediately below where you want the new case to appear
Click on Edit menu and Insert Cases
Delete variable – highlight the variable (column) and press Delete
Insert a variable between existing variables - move cursor to a variable (column) to the right of where you want the new variable to appear.
Click on Edit menu and Insert Variable
Useful SPSS Features
Split the data file – to run analysis for groups (violent offenders and non-violent offenders) Click on the Data menu and Split File
Click on Compare groups and specify the grouping variable (e.g. Type of criminal)
Click OK
Useful SPSS Features
Select Cases – e.g. only violent offenders in your analysis Click Data and Select Cases option
Click If condition is satisfied button
Click If
Useful SPSS Features
Choose the group variable (type of criminals) and move into the box
Click on the “=“ key and type in the value that corresponds to the group you are interested in
This example - Violent offenders = 2 Click Continue Click OK
Screening & Cleaning the Data
Step 1: Checking the Errors Checking categorical variables
Analyse, then click on Descriptive Statistics, then Frequencies
Screening & Cleaning the Data
Choose the variable and move it into Variable box
Screening & Cleaning the Data
Click on Statistics.
Tick Minimum and Maximum in the Dispersion section
Click Continue and OK
Check your Minimum and Maximum – Do they make sense?
Check Valid and Missing cases
Screening & Cleaning the Data
Statistics
Type of Criminals
N Valid 89
Missing 0
Minimum 1.00
Maximum 2.00
Type of Criminals
Frequency Percent Valid Percent
Cumulative
Percent
Valid 1.00 NonV 45 50.6 50.6 50.6
2.00 Violant 44 49.4 49.4 100.0
Total 89 100.0 100.0
Screening & Cleaning the Data
Checking continuous variables Analyze, then Descriptive statistics, then Descriptives.
Move your continuous variable into Variables box
Screening & Cleaning the Data
Click Options button
Click on the statistics
you wish to generate
Continue
OK
Screening & Cleaning the Data
Check the Minimum and Maximum values
Check the Mean
Screening & Cleaning the Data
Descriptive Statistics
N Minimum Maximum Mean Std. Deviation
Criminal Thinking 89 10.00 43.00 29.1685 7.90747
Valid N (listwise) 89
Case Summaries – allows you to select and display specific
pieces of information for each case
Analyze, go to Reports and choose Case Summaries
Screening & Cleaning the Data
Choose ID variable and other variables.
Remove the tick from the Limit cases to first 100
Screening & Cleaning the Data
Click on the Statistics and remove Number of cases from the Cell Statistics
Click Continue
Screening & Cleaning the Data
Click on Options and remove the tick from Subheadings for totals
Continue
OK
Screening & Cleaning the Data
SPSS Output
Screening & Cleaning the Data
Case Processing Summary
Cases
Included Excluded Total
N Percent N Percent N Percent
ID Number 89 100.0% 0 .0% 89 100.0%
Age 88 98.9% 1 1.1% 89 100.0%
Type of Criminals 89 100.0% 0 .0% 89 100.0%
Level of Recidivism 89 100.0% 0 .0% 89 100.0%
Criminal Thinking 89 100.0% 0 .0% 89 100.0%
Neuroticism 89 100.0% 0 .0% 89 100.0%
Extraversion 89 100.0% 0 .0% 89 100.0%
Psychoticism 89 100.0% 0 .0% 89 100.0%
Parental Supervision 89 100.0% 0 .0% 89 100.0%
Criminal Identity 89 100.0% 0 .0% 89 100.0%
Criminal Identity2 89 100.0% 0 .0% 89 100.0%
Criminal Identity3 89 100.0% 0 .0% 89 100.0%
Case Summaries
ID Number Age
Type of
Criminals
Level of
Recidivism
Criminal
Thinking Neuroticism Extraversion Psychoticism
Parental
Supervision Criminal Identity
Criminal
Identity2
Criminal
Identity3
1 1 3 36 and
more
2.00 Violant 3.00 35.00 5.00 6.00 3.00 12.00 25.00 30.00 40.00
2 2 2 26 - 35 1.00 NonV 3.00 40.00 1.00 4.00 6.00 12.00 25.00 30.00 40.00
3 3 2 26 - 35 1.00 NonV 3.00 32.00 3.00 5.00 3.00 10.00 22.00 32.00 40.00
4 4 3 36 and
more
1.00 NonV 4.00 24.00 3.00 5.00 1.00 23.00 17.00 27.00 37.00
5 5 3 36 and
more
1.00 NonV 1.00 10.00 1.00 3.00 2.00 24.00 -9.00 -9.00 -9.00
6 6 3 36 and
more
1.00 NonV 3.00 35.00 5.00 1.00 1.00 11.00 33.00 38.00 40.00
7 7 3 36 and
more
1.00 NonV 3.00 37.00 4.00 1.00 2.00 17.00 8.00 12.00 20.00
8 8 3 36 and
more
1.00 NonV 8.00 23.00 4.00 4.00 1.00 14.00 16.00 26.00 29.00
9 9 3 36 and
more
1.00 NonV 2.00 15.00 2.00 1.00 .00 18.00 21.00 31.00 40.00
10 10 2 26 - 35 2.00 Violant 1.00 23.00 6.00 4.00 1.00 8.00 22.00 32.00 40.00
11 11 2 26 - 35 2.00 Violant 1.00 21.00 3.00 1.00 2.00 15.00 18.00 28.00 38.00
12 12 2 26 - 35 2.00 Violant 4.00 41.00 5.00 6.00 1.00 12.00 21.00 28.00 38.00
13 13 3 36 and
more
2.00 Violant 2.00 27.00 .00 6.00 2.00 13.00 14.00 24.00 34.00
14 14 2 26 - 35 2.00 Violant 6.00 35.00 4.00 5.00 1.00 12.00 19.00 29.00 39.00
15 15 1 18 - 25 2.00 Violant 2.00 40.00 6.00 3.00 1.00 17.00 35.00 38.00 40.00
16 16 1 18 - 25 1.00 NonV 2.00 34.00 1.00 6.00 6.00 9.00 -9.00 -9.00 -9.00
17 17 2 26 - 35 1.00 NonV 4.00 24.00 3.00 6.00 1.00 13.00 13.00 23.00 25.00
18 18 2 26 - 35 1.00 NonV 3.00 37.00 6.00 6.00 3.00 13.00 30.00 35.00 40.00
19 19 1 18 - 25 2.00 Violant 2.00 42.00 4.00 6.00 4.00 15.00 23.00 33.00 40.00
20 20 3 36 and
more
1.00 NonV 10.00 43.00 5.00 6.00 3.00 13.00 26.00 36.00 40.00
21 21 2 26 - 35 1.00 NonV 1.00 28.00 2.00 3.00 2.00 14.00 21.00 31.00 40.00
22 22 1 18 - 25 1.00 NonV 2.00 28.00 2.00 5.00 1.00 14.00 12.00 22.00 32.00
23 23 1 18 - 25 1.00 NonV 2.00 31.00 2.00 6.00 2.00 10.00 18.00 28.00 38.00
24 24 1 18 - 25 2.00 Violant 4.00 27.00 1.00 6.00 1.00 15.00 20.00 30.00 40.00
25 25 3 36 and
more
1.00 NonV 1.00 36.00 5.00 3.00 1.00 17.00 19.00 29.00 39.00
26 26 3 36 and
more
2.00 Violant 1.00 25.00 .00 5.00 3.00 16.00 8.00 18.00 28.00
27 27 2 26 - 35 1.00 NonV 2.00 21.00 3.00 4.00 1.00 13.00 10.00 20.00 30.00