Introductory Workshop SPSS

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Introductory WorkshopSPSS

• CSU Bakersfield
• April 17, 2009

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Social Science Research and Instructional Council
(SSRIC)

• Discipline council for the social sciences made
  up of representatives from each campus in the
  CSU. List of campus representatives can be found
  at http//www.ssric.org/reps
• Promotes use of data analysis in research and
  teaching
• Website is at http//www.ssric.org

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Social Science Data Bases

• The SSRIC helps maintain and promote the use of
  the social science data bases in the CSU
• Data bases include
• Inter-university Consortium for Political and
  Social Research (ICPSR)
• The Field Institute
• The Roper Center for Public Opinion Research

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Agenda for the Introductory SPSS Workshop

• Overview of SPSS
• A brief tour
• Creating youre your own SPSS data file or
  opening a data file you got somewhere else
• Transforming data
• Recode
• Compute
• Select If
• Univariate analysis
• Frequencies
• Descriptives
• Explore
• A look ahead at the intermediate workshop

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Overview of SPSS

• SPSS is a statistical package for beginning,
  intermediate, and advanced data analysis
• Other statistical packages include SAS and Stata
• Online statistical packages that dont require
  site licenses include SDA

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Text SPSS for WindowsVersion 16 A Basic
Tutorial

• Authors Linda Fiddler (Bakersfield), Laura Hecht
  (Bakersfield), Ed Nelson (Fresno), Elizabeth
  Nelson (Fresno), Jim Ross (Bakersfield)
• Available from McGraw-Hill Custom Publishing.
  Call 800-338-3987 to order. Request ISBN
  0-07-353833-7
• Available on the web at http//www.ssric.org/trd/s
  pss16. The data set for this workshop can be
  downloaded at this site

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SPSS Files and Extensions

• Portable file -- .por
• Data file -- .sav
• Output file -- .spo
• Syntax file -- .sps

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Opening SPSS

• Go to start and find SPSS for Windows
• Click on SPSS 16.0 or 17.0 for Windows to open
• Youll need to update your SPSS license every
  year (or your school technician will do it for
  you)

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A Brief Tour of SPSS(see ch. 1 in text)

• Frequencies -- Analyze/Descriptive
  Statistics/Frequencies
• Select ABANY and move it to the big box and click
  on OK
• Crosstabs Analyze/Descriptive
  Statistics/Crosstabs
• Move ABANY to the Row box
• Move SEX to the Column box
• Click on Cells and select Column percents
• Click on OK

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A Brief Tour Continued

• Comparing means Analyze/Compare Means/Means
• Move AGEKDBRN and EDUC in the Dependent List
  box
• Move SEX to the Independent List box
• Click on OK

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A Brief Tour Continued

• Correlations
• Analyze/Correlate/Bivariate
• Move EDUC, MAEDUC, and PAEDUC into the
  Variables box
• Click on OK

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A Brief Tour Continued

• Scatterplots
• Graphs/Legacy Dialogs/Scatter/Dot
• Click on Simple Scatter and then on Define
• Move EDUC into the Y axis box
• Move PAEDUC into the X Axis box
• Click on OK

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Creating Your Own SPSS Data File(see ch. 2 in
text)

• Involves creating
• Variable names
• Variable labels
• Value labels
• Missing values

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Creating a Data File in SPSS

• Questions (see p. 11)
• Age
• Sex
• Religious preference
• Type of marriage preferred
• Opinion on abortion (7 different questions)

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Basic Steps in Creating a Data File

• Assign identification number to each case
• Assign each variable a variable name and an
  extended variable label
• Each variable will have a set of values. Assign
  each value an extended value label
• If a variable has missing information, decide
  which values will be used as the missing values

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Variable Names

• Traditionally variable names had to be 8
  characters or less, start with a letter, and
  contain no embedded blanks
• Now they can be longer than 8 characters, but
  well stick with names of 8 or fewer characters
• Names can contain some special characters, but
  not all such characters. So we only use hyphens
  (-) as special characters in names

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Variable Names

• Age is named AGE
• Sex is named SEX
• Religious preference is named REL
• Political orientation is named C-L
• Preferred marriage is named MG
• There are seven abortion variables and they are
  named ABD, ABN, ABH, ABP, ABR, ABS, ABA

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Entering the Information for a Data File

• You already have SPSS open
• Click on File/New/Data
• You should see a blank data screen that looks
  like a spreadsheet
• At the bottom are two tabs called Data View and
  Variable View. Click on Variable View

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Defining the Variables

• Enter the variable names in the Names columns
  in the order you want them
• Enter the variable labels in the Label column
• Enter the value labels in the Values column.
  To do this you will need to click in the
  appropriate cell and then click in the little
  gray box on the right
• Enter the missing values in the Missing column.
  To do this you will need to click in the
  appropriate cell and then click in the little
  gray box on the right

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Adding in the Data

• Now that you have defined the variables, click on
  the tab at the bottom called Data View and
  enter the data into the appropriate cells. The
  data are on p. 18 of the text
• Once you have entered the data, go back and check
  to make sure you didnt make any data entry
  errors
• Congratulations!! you created a SPSS data file.
  You could also enter the data using a
  spreadsheet like Excel

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Saving the Data File

• Now you want to save your data file
• Click on Save as. The default is to save it as
  a SPSS data file with .sav as the extension
• Give it a file name and indicate where you want
  to save it on your hard drive or on your floppy
  or flashdrive

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Opening an Existing File You Got Somewhere Else

• Often you will want to open a data set that you
  got from someplace else such as
• ICPSR
• Field Institute
• Roper Center
• These files will usually be in the form of a
• SPSS portable file (.por)
• SPSS data file (.sav)
• Raw data file with a SPSS syntax file (.sps)
• Raw data file without a syntax file

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Opening a Portable file

• Click on the open yellow folder to open a new
  file
• Change file type to .por
• Browse to where the portable file you want to
  open is located and double click on that file

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Opening an SPSS Data File

• Click on the open yellow folder to open a new
  file
• Change file type to .sav
• Browse to where the data file you want to open is
  located and double click on that file
• Were going to use the data set that comes with
  the text gss06a.sav. You can download it from
  the web site that has the text --
  http//www.ssric.org/tr/onlinetextbooks. Look
  for the text Right click here to download
  GSS06A.

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Opening a Raw Data File with a SPSS Syntax File

• Sometimes you will need to open a raw data file
  (ASCII or text) and there will be an accompanying
  SPSS syntax file
• You will need to modify the File Handle and
  Save Outfile commands
• See http//www.ssric.org/files/ASCII_to_SPSS.pdf
  and http//www.icpsr.umich.edu/cocoon/ICPSR/FAQ/00
  62.xml for more information
• You may need help doing this. Feel free to
  contact me for help

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Opening a Raw Data File Without a SPSS Syntax
File

• If you dont have a SPSS syntax file you will
  have to use the codebook that came with the data
  and create your own syntax file
• You may need help doing this. Feel free to
  contact me for help

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Whats Next?

• Now you know how to create a SPSS data file and
  how to open an existing SPSS portable or data
  file
• Next well learn how to transform variables

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Transforming Data(see ch. 3 in text)

• We can transform variables by recoding which
  means to combine categories on an existing
  variable into fewer categories
• We can transform variables by creating new
  variables out of existing variables
• We can select particular cases and analyze only
  these cases
• We can do other things like weighting cases that
  were not going to talk about in this workshop.

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Recoding Variables

• Recoding into different variables
• Recoding into the same variable
• We recommend recoding into different variables
  and not using the into same variable option

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Recoding into Different Variables

• Click on Transform and then on Recode and
  then on into different variables
• Select the variable you want to recode
• Start by giving the new variable a new name and
  assigning a variable label to the new variable.
  Click on Change

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Recoding AGE into AGE1

• Recode AGE into four categories and give it the
  name of AGE1
• Click on Old and New Values
• Use Range (fourth option down) to recode as
  follows. Remember to click on Add after
  entering each recode
• 18 to 29 1
• 30 to 49 2
• 50 to 69 3
• 70 to 89 4

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Recoding Options

• When you click on Old and New Values there will
  be seven options
• For most recoding you will only have to use two
  of these options
• The first option from the top allows you to
  recode a single value into a new value
• The fourth option from the top allows you to
  recode a range of values from X to Y into a new
  value

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Assign Value Labels to the Four Categories of
AGE1

• Go into Variable View
• Find the variable AGE1 (should be at the bottom
  of the list of variables)
• Click in the Values column and then click on
  the small gray box
• Enter the value labels
• Click on OK

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Exercises for Recoding

• INCOME06 is total family income. Do a frequency
  distribution to see what it looks like before
  recoding
• Recode into 4 categories and call this new
  variable INCOME1. Use the following categories
  under 20K, 20K to under 40K, 40K to under
  60K, and 60K and over
• Add the value labels
• Run a frequency distribution for INCOME1 and
  check to make sure that you recoded it correctly
  by comparing the unrecoded and recoded frequency
  distributions

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More Exercises for Recoding

• Now recode INCOME06 again and call the new
  variable INCOME2
• This time use 8 categories under 10K, 10K to
  under 20K, 20K to under 30K, 30K to under
  40K, 40K to under 50K, 50K to under 60K,
  60K to under 75K, and 75K and over
• Add the value labels
• Run a frequency distribution for INCOME2 and
  check to make sure that you recoded it correctly
  by comparing the unrecoded and recoded frequency
  distributions

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Creating a New Variable with Compute

• Lets create a new variable and call it ABORTION
  which is the sum of the seven abortion variables
• Click on Transform and then on Compute
• Enter the new variable name (ABORTION) into the
  target variable box
• Enter the formula for this new variable into the
  Numeric Expression box
• Click on OK

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Dealing with Missing Data

• If there is missing data for any of these
  variables (ABANY to ABSINGLE), the new variable
  ABORTION will be assigned a system missing value
• What do we do if we want to allow no more than
  two missing values?
• Lets compute the mean value and divide the sum
  of the abortion values by the number of cases
  with valid information
• But lets allow only two variables with missing
  values

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Dealing with Missing Data Continued

• Click on Reset to erase what is currently in
  the Compute Variable box
• Click on Statistical in the Function Group
  box
• Then double click on Mean in the Function and
  Special Variables box
• In the Target Variable box, enter the name of
  the new variable. Lets call it ABORMEAN
• In the Numeric Expression box, you should see
  MEAN(?,?)

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Dealing with Missing Data Continued

• Replace the ?,? with the variables you want to
  include so it reads MEAN (abany,abdefect,abhlth,a
  bnomore,abpoor,abrape,absingle)
• Insert .5 following MEAN so it reads Mean.5.
  This indicates that you want to have at least
  five variables with valid information
• Click on OK

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Exercises for Compute

• There are five variables that measure tolerance
  for letting someone speak in your community who
  may have different views than your own SPKATH,
  SPKCOM, SPKHOMO, SPKMIL, and SPKRAC
• For each of these variables, 1 means they would
  allow such a person to speak and 2 means they
  would not allow it

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Exercises for Compute Continued

• Create a new variable (call it SPEAK) which is
  the sum of these five variables
• Run a frequency distribution for SPEAK
• What do the values in this new variable tell us?

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More Exercises for Compute

• Now lets create a variable called SPKMEAN which
  allows for one of the five variables (SPKATH to
  SPKRAC) to be missing
• What happens if there is more than one variable
  with a missing value?
• How does SPSS calculate the new variable if there
  is only one variable with a missing value?

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Using Select Cases to Select Specific Cases for
Analysis

• Lets select only Protestants for further
  analysis
• Click on Data and then on Select Cases
• Click on If condition is satisfied and then on
  the If button below it
• Select the variable RELIG and move it into the
  box on the right
• In this box, enter the expression relig 1
• Click on Continue and on OK

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Using Select Cases Continued

• Now lets select Protestants who are under 35
  years age old
• Enter the expression relig 1 as you did
  before.
• Use for and. Enter age lt 35 so the
  expression reads relig 1 age lt 35
• Click on OK

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Exercises for Select If

• Select all males (1 on the variable SEX) and do a
  frequency distribution for the variable FEAR
  (afraid to walk alone at night in the
  neighborhood)
• Now select all females (2 on the variable SEX)
  and fun a frequency distribution for FEAR
• Are males or females more fearful of walking
  alone at night?

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More Exercises for Select If

• Now lets select males under age 35 and run a
  frequency distribution for FEAR
• Do the same thing for females under 35
• Are males or females under 35 more fearful of
  walking alone at night?

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Important Note on Using Select Cases

• When you are finished using Select Cases and
  want to revert to using all the cases be sure to
  click on Data/Select Cases and select All
  cases. Then click on OK
• If you dont do this, you will continue to use
  only those cases you last selected

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Univariate Analysis

• Now that we know how to open existing files and
  transform variables, were ready to begin
  analyzing data
• Univariate analysis refers to analyzing variables
  one-at-a-time

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Types of Univariate Analysis Procedures (see
ch. 4 in text)

• Frequencies
• Descriptives
• Explore

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Frequencies

• Go to Analyze/Descriptive Statistics/Frequencies
• Select ABANY and AGE and click on OK

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Bar Charts

• Bar charts click on Analyze/Descriptive
  Statistics/Frequencies
• Click on Charts
• Select Bar Charts and click on Continue and
  then on OK
• Do you think bar charts are appropriate for both
  ABANY and AGE?

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Histograms

• Click on click on Analyze/Descriptive
  Statistics/Frequencies
• Click on Charts
• Select Histograms and click on Continue and
  then on OK
• Do you think histograms are appropriate for both
  ABANY and AGE?
• Which do you think is the most appropriate chart
  (bar chart or histogram) for ABANY and for AGE?

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Statistics

• Click on Analyze/Descriptive Statistics/Frequencie
  s
• Click on Statistics
• Select the statistics you want and click on
  Continue and then on OK

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Exercises for Frequencies

• There are seven variables dealing with abortion
  ABANY, ABDEFECT, ABHLTH ABNOMORE, ABPOOR, ABRAPE,
  and ABSINGLE
• Run a frequency distribution for each variable
• Get a bar chart for each variable
• Compare and contrast how people answered these
  seven questions

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More Exercises for Frequencies

• Run the frequency distribution for AGE
• Get a histogram for AGE
• Compute the following statistics for AGE
• Mean
• Median
• Standard deviation
• Percentiles 25th, 50th, and 75th

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Descriptives

• Click on Analyze/Descriptive Statistics/Descriptiv
  es
• Select AGE and EDUC
• Click on Options and select the statistics you
  want and then click on Continue and OK

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Exercises for Descriptives

• Use Descriptives to compute the following
  statistics for AGE
• Mean
• Standard deviation
• Variance
• Skewness
• Kurtosis

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More Exercises for Descriptives

• Use Descriptives to compute the mean for EDUC,
  MAEDUC, PAEDUC
• Who has the most education respondents or their
  parents?
• Who has the most education mothers or fathers?

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Explore

• Click on Analyze/Descriptive Statistics/Explore
• Select EDUC and put it in the Dependent List
• In the Display box on the lower left, click on
  Both
• Click on OK

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Selecting Statistics for Explore

• Click on Analyze/Descriptive Statistics/Explore
• Click on Statistics and select the statistics
  you want
• Click on Continue and then OK

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Selecting Plots for Explore

• Click on Plots
• Select the plots you want
• Click on Continue and then OK

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Exercises for Explore

• Using Explore to get the following statistics and
  plots for the variables EDUC, PAEDUC, and MAEDUC
• Descriptives
• Outliers
• Stem-and-leaf plot
• Histogram
• Boxplot
• First select Factor levels together and run it
• Then select Dependents together and run it
  again
• Whats the difference?

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Intermediate Workshop for SPSS

• In the next workshop well look at different
  types of statistical analysis you can do in SPSS
• Cross tabulations (ch. 5)
• Comparing means (ch. 6)
• Correlation and regression (ch. 7)
• Multivariate analysis (ch. 8)
• Cross tabulations
• Multiple regression
• Presenting your data charts and tables (ch. 9)