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SPSS. Recently it has gone through a name change so your icon on your computer may be under a different name (i.e. PASW- Predictive Analytics SoftWare). IBM purchased the company and said they are going to change the name to IBM-SPSS or SPSS: An IBM Company. What is SPSS?.
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SPSS • Recently it has gone through a name change so your icon on your computer may be under a different name (i.e. PASW- Predictive Analytics SoftWare). • IBM purchased the company and said they are going to change the name to IBM-SPSS or SPSS: An IBM Company
What is SPSS? • Statistical software: • Statistical Package for the Social Sciences • There are lots of others • SAS • STATA • R • SHAZAM • Specialized software • HLM • LISREL • BUGS
Why SPSS? • Although SPSS is not the most powerful statistical software - It is the easiest to learn and use!!!!!! • It is very flexible and can do most everything we need • It can examine a large amount of data very quickly • It is competitively priced
Where to start? • Get some data • In practice you would develop a research question first, a theory, hypotheses, etc. before collecting and analyzing data
Sources of data • ICPSR - http://www.icpsr.umich.edu/icpsrweb/ICPSR/ • Free for universities that subscribe (UNLV does) • For now we have a dataset on our course website and WebCampus • http://faculty.unlv.edu/kfernandez/methods1.htm
General Social Survey • NORC (National Opinion Research Center) located at the University of Chicago • Telephone survey since 1972 • Free to anyone • http://www.norc.org/GSS+Website/ • It is big so use the edited 2002 version located on our course website
General Social Survey • The dataset is huge with hundreds of survey items (variables). • The dataset we are using today has been edited to include only 47 variables • This is also an older dataset (sometime after 1996). • The NORC website has a free 2010 version if you are interested. • This could be a dataset you use for your research design assignment
The Basics • This is a one level, rectangular dataset • What do the rows represent? • What do the columns represent? • This dataset could be connected to other datasets to create multiple-level datasets • i.e. individual, state, country
First things first • Setting the options will make life easier • Go to the pull down menu “edit” • Select “Options” • Select the “General” tab at the top • Under “Variable List” click Display Names and Alphabetical • Now select the “Output Labels” tab • Make sure they all say Names and Labels or Values and Labels
Lets get our feet wet • Most tools will be under the “analyze” pull down menu • Select “Descriptive Statistics” and then “Frequencies” • Find the variable “Tvhours”. The list should be alphabetical now. Move it to the “Variables” box and click ok. • What does this table mean?
Missing Data and Outliers • Is there anything strange in any of the responses? • What about missing data? • How many respondents didn’t answer the question? • NAP = Not Appropriate; NA = Not Answered
Recoding • Variables often need to be cleaned or recoded so that they can be used in a statistical model • For example find the variable “income” • Run a frequency • There is a value that if not changed will really mess up your analysis • What is it and why is it a problem? • What do we need to do?
Recoding • Select the “Transform” pull down menu • Click the recode into the same variable • WARNING, WARNING • Usually I choose the “recode into different variable” because if you make a mistake you will forever change that variable and won’t be able to go back. Always have a backup of your dataset that is untouched so you can start over if you need to.
Recoding • Select “income” • Click “Old and New Values” • In the Old Value type “24” • In the new value select “System-Missing” • Click “Add” • Click “Continue” • Now Click OK • Rerun the frequency for income • Now 23 is the highest value, not “refused”