Create a new folder in your network drive Z. You can use it during
this course to save your SPSS-related work such as graphs, tables and
your interpretations. Open the executable SPSS version PASW 18. Explore
and familiarize yourself with the views and menus of SPSS. The Data
Editor window has two views, between which you can select by clicking
on the Data View and Variable View tabs in the bottom left corner of
the window. What’s the difference between these two views? Find out
also, what are the Syntax and Output windows.
- SPSS Windows, Menus and Toolbars.
- On SPSS Data vs. Variable view, see SPSS Tutorial Help/Tutorial/Using the Data Editor/Using the Data Editor
Do you remember the difference between continuous and categorical
variables? Create variables in SPSS’s Variable
View based on the background questions in the sample questionnaire.
Give the variables both a name and a label. The name can’t be longer
than 8 characters and the maximum length of a label is 255 characters. (Actually they can be longer, but if you want to keep your data compatible with older versions of SPSS, it might be a good idea to keep to these limits.) Descriptive and thought-out variable names and labels make the data
much more accessible to others, and even to yourself, if you find
yourself coming back to a data you haven’t looked at for a while.
If the variable doesn’t need decimal notation, change the amount of
decimals to zero from the default setting of two digits. If the
variable is categorized, enter the category labels at the column
marked “Values” by clicking the cell first, and then clicking the grey
dotted box. The variable type is mostly self-explanatory: the type is
set to “string”, when the variable contents are non-numeric, such as
answers to open-ended questions.
Enter the questionnaire data from all of the six respondents to SPSS. You need
to use the Data View for this. Enter the values one observational unit
(i.e., one row in SPSS Data View) at a time. Save the data in your course folder
- On entering data, see SPSS tutorial Help/Tutorial/Using the Data Editor/Entering Numeric Data and Help/Tutorial/Using the Data Editor/Defining Data
- An explanation on the differences of discrete and continuous variables, levels of measurement, and continuous and categorical variables
Examining Basic Statistics
Recall the possible levels of measurement for variables, and what kind
of statistics can be calculated from variables of different levels of
Open the course data, and save it in your course
folder. From now on, we will use this data for all
exercises. Familiarize yourself with the variables by examining the
variables and questions. While looking through
the questions, think about the variable classes. Which of the variables are
categorical, and which are continuous?
Pick a couple of variables from the data, for example Gender (gndr), Father’s highest level of education (edulvlf), Hours you spend studying, how many an average term-time week (stdhrsw), and examine some of
their descriptive statistics such as mean, standard deviation, minimum and
maximum (Analyze/Descriptive Statistics/Frequencies or Analyze/Descriptive
Contemplate on the various interpretations the different statistics can
have, and write a short summary on them.
Hint: When using the dialog window instead of the Syntax window to choose variables in SPSS, sometimes it’s rather frustrating trying to find the variable you’re looking for. If you know the letter the variable description begins with, you can press that letter on your keyboard to cycle through the variables. To see the full variable description, hover the mouse pointer over the variable in question. E.g. when trying to find the variable ‘stdhrsw’ you would keep pressing ‘h’ until you see a description that begins like ‘Hours you spend studying…’.
- <a href="http://www.socialresearchmethods.net/kb/statdesc.htm"Descriptive statistics
- Levels of measurement
Graphs and Histograms
Bar graphs can be used to examine the distributions of discrete
variables. Pick one discrete variable and make a bar graph
(Graphs/Legacy Dialogs/Bar/Simple). Move your variable to the slot labeled
“Category Axis“. Examine the bar frequencies and write a short
analysis based on your findings.
A histogram can be used to display distributions of continuous
variables. Pick one variable, and draw a histogram
(Graphs/Legacy Dialogs/Histogram). Move your variable to the slot labeled
“Variable“. Examine the resulting histogram. Does the
variable appear to be normally distributed?