Course Code: SPSS19 Introduction to IBM SPSS Statistics

Transcription

1 Centre for Learning and Academic Development (CLAD) Technology Skills Development Team Course Code: SPSS19 Introduction to IBM SPSS Statistics

2 An Introduction to IBM SPSS Statistics Author: Sonia Lee Cooke Acknowledgement: Thanks to Dr. Sayeed Haque for his valuable contributions throughout the development of this course. Version: 1.0, January The University of Birmingham All rights reserved; no part of this publication may be photocopied, recorded or otherwise reproduced, stored in a retrieval system or transmitted in any form by any electrical or mechanical means without permission of the copyright holder. Trademarks: Microsoft Windows is a registered trademark of Microsoft Corporation. All brand names and product names used in this handbook are trademarks, registered trademarks, or trade names of their respective holders.

3 Contents Page No. ABOUT THE WORKBOOK... 1 INTRODUCTION... 3 WHAT IS IBM SPSS STATISTICS... 3 PREPARING DATA FOR ANALYSIS... 3 SAMPLE QUESTIONNAIRE... 3 CODING... 4 STARTING IBM SPSS STATISTICS THE IBM SPSS STATISTICS DATA EDITOR WINDOW... 7 THE MAIN MENU AND TOOLBAR... 8 THE FILE MENU... 8 THE EDIT MENU... 9 THE VIEW MENU... 9 THE DATA MENU THE TRANSFORM MENU THE ANALYZE MENU THE GRAPHS MENU THE UTILITIES MENU THE ADD-ONS MENU THE WINDOW MENU THE HELP MENU THE TOOLBAR INPUTTING DATA WORKING IN VARIABLE VIEW Defining Variable names WORKING IN DATA VIEW EDITING VALUES AND VARIABLE NAMES INSERTING CASES AND VARIABLES DELETING CASES AND VARIABLE NAMES SPLITTER CONTROL SAVING A DATA FILE OPENING A DATA FILE RUNNING AN ANALYSIS SELECTING CASES CREATING A FREQUENCY TABLE IBM SPSS STATISTICS VIEWER Working with SPSS Output SPLIT FILE CREATING A DESCRIPTIVES TABLE RECODING CROSS TABULATION COMPUTE FUNCTION CREATING CHARTS LEGACY DIALOGS CHART BUILDER EDITING CHARTS An Introduction to IBM SPSS Statistics 19 Page 1

4 Changing the chart colour Change the Y-axis scale Change the title Displaying data value labels A STUDY OF THE WONDERFUL PEOPLE WHO COME ON RESEARCH SKILLS TRAINING COURSES IN THE WEST MIDLANDS. 3

5 About the workbook The workbook is designed as a reference for you to use after the course has finished. The workbook is yours to take away with you so feel free to make any notes you need in the workbook itself. The workbook is divided into sections with each section explaining about a particular feature of the program or how to do a particular task. Sections that take you through a particular procedure step-by-step look like this: How to do something Do this first. Then do this. Then do this to finish. There are also a number of text boxes to watch out for throughout the workbook. These will help you to get the most out of the course. Tip The thumbs-up symbol in the margin indicates a tip. These tips will help you work more effectively. Danger! The thumbs-down picture in the margin indicates common mistakes or pitfalls to be avoided. An Introduction to IBM SPSS Statistics 19 Page 1

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7 Introduction Quantitative research can involve processing data which can be collected in many different ways depending on the nature of your research; it could come from responses from questionnaires, information collected from interviews, or experiment. SPSS provides a wide range of capabilities that will help you to manage the wealth of information. What is IBM SPSS Statistics SPSS is a statistical software package which runs under windows and the Apple Macintosh. It is designed for managing and analyzing quantitative data. During the 1960s SPSS initially stood for Statistical Package for the Social Sciences. In 2009 it was re-branded as PASW (Predictive Analytics SoftWare), and now it is known as IBM SPSS Statistics 19. The University of Birmingham have been using SPSS for over 30 years. It is in great demand by users and far more popular than all the other statistical packages. This document was written to accompany the IBM SPSS Statistic course (An Introduction to IBM SPSS Statistics 19). This course is intended for those who are new to SPSS and with the aid of a sample questionnaire; this course provides an overview of the basic features of SPSS. Preparing data for analysis Sample questionnaire An Introduction to IBM SPSS Statistics 19 Page 3

8 There are a number of procedures that needs to be carried out before you can use SPSS such as understanding how SPSS works; preparing data in order to enter it into SPSS and translate the data you have into a format suitable for SPSS. You should also have a good idea of how you are going to analyse the data before you start to collect it, if not, this may lead to difficulties when you come to analyze your data. Coding SPSS can only analyse numbers. Therefore, you need to code your nonnumeric data into numbers. We used the above questionnaire to collect data about people who came on the Research Skills Training courses in the West Midlands. The following two questions were taken from the questionnaire: 1. How satisfied are you with your job were measured as: very satisfied, fairly satisfied, no opinion, a little dissatisfied and very dissatisfied 2. We also collected data on peoples gender A numerical code must be assigned to each response before the data is entered into SPSS as shown below: Gender: Male = 1, Female = 2 Or Male = 2, Female = 1 How satisfied are you with your job: very satisfied = 1 fairly satisfied = 2 no opinion = 3 a little dissatisfied = 4 very dissatisfied = 5 Or very dissatisfied = 1 a little dissatisfied = 2 no opinion = 3 fairly satisfied = 4 very satisfied = 5 Page 4 An Introduction to IBM SPSS Statistics 19

9 Starting IBM SPSS Statistics 19 To start SPSS do one of the following: From one of the computers in a cluster on campus, click on the Start button at the bottom left of the screen Click on All Programs, click on [ITS Applications], click on IBM SPSS Statistics, IBM SPSS Statistics 19. Click on the Start button, select Programs, IBM SPSS Statistics 19. If you have an IBM SPSS Statistics 19 icon on the desktop double click on it. The IBM Statistics 19 dialogue box appears: Under What would you like to do? You can choose from six options by clicking on one of the radio buttons to select the required option. You can run the tutorial, type in data, open an existing data source or open another type of file from different software. By default the Open an existing data source is selected: To create a new data file, select Type in data and click on the OK button at the bottom of the IBM SPSS Statistics 19 dialogue box. An Introduction to IBM SPSS Statistics 19 Page 5

10 This automatically opens the IBM SPSS Statistics Data Editor window. At the top of the window are the following items: Title bar Menu bar Toolbar At the bottom of the window are: The Data View tab The Variable View tab The Status bar Page 6 An Introduction to IBM SPSS Statistics 19

11 The IBM SPSS Statistics Data Editor window The IBM SPSS Statistics Data Editor window looks like a spreadsheet. However, it does not work like one; you cannot enter formulas into the cells. It is for creating and editing SPSS data files. The diagram below shows the Data View window. Menu bar majority of SPSS procedures can be accessed by making selections from the menus Title bar displays Untitled1 [DataSet0] IBM SPSS Statistics Data Editor and when you open another new data file, the title will change to [DataSet1] etc until you save the data file. The untitled label is replaced by the file name Close window Maximise window Minimise window Toolbar to access the most frequently used functions Variable names. Columns represent variables Rows represent cases or observations Variable View - this view is used to create the names and details of the variable in your data set Data View is currently active; this view is used to enter data or view information already created Cells Status bar displays information on procedures that you run, each box to the right of IBM SPSS Statistics Processor is ready will display a different message depending on what you are working with An Introduction to IBM SPSS Statistics 19 Page 7

12 The Main menu and Toolbar The vast majority of IBM SPSS Statistics functions can be accessed through the menus. There are 11 drop-down menus which are located at the top of the IBM SPSS Statistics window; details of the menus are listed below, together with information on the most commonly used functions on the toolbar. The File menu The File menu allows you to create a new IBM SPSS Statistics data file, open an existing data file, save a data file, and import a database from MS Access or Read Text Data from an MS Excel workbook and other functions listed on the drop-down menu. Page 8 An Introduction to IBM SPSS Statistics 19

13 The Edit menu You can use the Edit menu to modify the data file and change the general default options for various functions such as charts, data view and viewer. The View menu The View menu allows you to view or hide different type of items such as the Status bar at the bottom on the screen, toolbars, change fonts, hide or show grid lines, value labels to change the view from text to numeric values and switch between variables and data views. An Introduction to IBM SPSS Statistics 19 Page 9

14 The Data menu The Data menu displays a list of various options such as sort cases, split file and select cases. See pages 24 to 30 for more details on select cases and split file. The Transform menu The Transform menu displays a list of various options such as calculate variable and recode new variable based on the values of existing ones. See page 32 and 36 for more details on recode into different variables and compute variable. Page 10 An Introduction to IBM SPSS Statistics 19

15 The Analyze menu The Analyze menu displays a list of various statistical procedures; this course will only cover some of the Descriptive Statistics functions such as frequencies, descriptives and crosstabs. See Page 28, 34 and 35 for more details. The Graphs menu The Graphs menu allows you to create various different types of charts such as bar chart, pie charts, boxplot, histogram scatterplot and others. See Page 36 for more details. An Introduction to IBM SPSS Statistics 19 Page 11

16 The Utilities menu The Utilities menu allows you to view variables definition information, add and display descriptive comments to a data file, spell check your data and various other functions. The Add-ons menu You can use this menu to download a chapter sample of the Statistics guides and various Add-ons functions. Page 12 An Introduction to IBM SPSS Statistics 19

17 The Window menu The Window menu allows you to split the screen into two or more sections in order to view a wide data set. (See page 23 for more details) A list of currently used data files is also displayed. The Help menu You can use the help Topics on the Help menu to learn about specific tasks, Statistics Coach provide a wide range of quick step-by-step instructions that guide you through the process of many of the basic, commonly used statistical techniques and for detailed examples of various statistical analysis techniques use Case Studies. An Introduction to IBM SPSS Statistics 19 Page 13

18 The Toolbar Open an existing Data file Open Save a data file. Save Print a data file. Print Displays a list of recently used dialogue boxes, which you can access. Recall Recently used Dialogs Undo and Redo. Undo Redo Go to Case Displays the Go To dialogue box which allows you to go to any case (row) within the data. Enter the case number in the text box and click on the Go button Go to Variable Displays the Go To dialogue box which allows you to go to any variable (column) within the data. Click on the arrowhead to view the list of variable names, select the variable name and click on the Go button. Page 14 An Introduction to IBM SPSS Statistics 19

19 Provides information on each of the variables in the data set. Variables Find In Data view you can find and/or replace the data value only in a single column of the data set. Click on the first cell of the column that contains the data you want to fine, then click on the Find button. Note: You can only search in the Down direction in Data view. Insert Cases Insert Variables In Data View, click on the Insert Cases button to insert new case(s) above the cursor s position (a case is a row) In Variable View, click on the Insert Variables button to insert a new variable above the cursor s position. In Data view, the new variable is inserted to the left of the cursor s position (a variable is a column) Split file allows you to split the data file into separate groups for analysis. Split File Weight Cases Weight Cases indicate the number of observations represented by single cases in your data file, can be used for Chi-square on summarized data. Select Cases allows you to perform an analysis on a subset of cases. Select Cases Value Labels allows you to view the labels or numeric values in your data set. Value Labels An Introduction to IBM SPSS Statistics 19 Page 15

20 Use Variables Set The list of available variable sets includes any variable sets defined for the active dataset, plus two built-in sets: All Variables and New Variables (shown below). ALLVARIABLES. This set contains all variables in the data file, including new variables created during a session. NEW VARIABLES. This set contains only new variables created during the session. You cannot add a new variable to the dataset unless you have the NEW VARIABLES selected. Check for misspelled items in Data View, Variable View and Value labels Spell Check Inputting Data The SPSS Statistics Data Editor window has two views which are located at the bottom of the window: Variable view - when you are entering data for the first time, you must use this view to define the variable names. Data view use this view for entering, editing and displaying data, after you have defined the variable names. Working in Variable View To define variable names, ensure you are in the variable view. You must create the variables in this view before entering the data. Defining Variable names To define the names and details of each variable in your data set: Click on the Variable view tab (if it s not active) Page 16 An Introduction to IBM SPSS Statistics 19

21 Tip: You can also double-click on any one the variable names (column heading in the Data view window) to switch to the Variable View window. Or press Ctrl T to toggle from Variable View to Data View. The Variable view window appears: There are pre-defined attributes at the top of each column. You can use these attributes to define the variables and insert a description for each variable in your data set. Variable names are entered in rows and the variable attribute in the columns. The first variable in a data set must be ID (a unique number that identifies each case). See below for information on each variable: Your Variable names should be short and meaningful. Each variable must have a different name. If no name is entered SPSS will use the default name (VAR0001, VAR0002 etc ) for each variable. You can have up to 64 characters, however, variable name that exceeds eight characters are not displayed in the variable list, and you may have to resize the column. No spaces are allowed in each variable. If you enter characters that are not allowed, such as * - /!, the following dialogue box will appear: The name must start with a letter, names can contain the following characters: _ (underscore), $, #, An Introduction to IBM SPSS Statistics 19 Page 17

22 To define the type of variable, click in the cell below the Type heading. Click on the grey button with three dots to display the Variable Type dialogue box: The default variable type is Numeric, the standard default width is eight characters, and cannot exceed 40 characters. The decimal places are two characters, and cannot exceed 16 characters. If you change the values of the Width and Decimal Places within the Variable Type dialogue box it will also reflect in the Width and Decimals cells (listed below). Comma, Dot, Scientific notation, Dollar and Custom currency are not commonly used. Dates are listed in several different formats and can be entered with slashes, hyphens, full-stops, commas, or blank spaces as delimiters: Page 18 An Introduction to IBM SPSS Statistics 19

23 Select a date format from the list, e.g. if you select dd-mmm-yyyy the current date will be displayed in the following format style: 21-Jan Select the required option. Numeric and String are the most commonly used options. String is for recording names or other text, you cannot exceed 32,767 characters. String should only be used if it s absolutely necessary. Click OK to return to the Variable view. You can enter up to 40 characters for the width. Click on the spinner (arrow up/down) to increase or decrease the width. You can have from 0 to 16 decimals places. Click on the spinner (arrowhead up/down) to increase or decrease the decimals places. You can assign descriptive variable labels that can contain spaces and special characters that are not allowed in the variable name. You can have over 255 characters. You can define values by selecting the cell below the heading. Click on the grey button with the three dots to display the Value Labels dialogue box: Enter the number in the Value text box eg, let say you have coded, 1 = Male and 2 = Female. Enter 1 in the Value text box. Enter Male in the Label text box. (You can enter up to 120 characters). An Introduction to IBM SPSS Statistics 19 Page 19

24 Click on the Add button. Repeat above instructions until you have entered all the values. Click on the OK button. You might want to distinguish between data that are missing because a respondent refused to answer a question or the question didn't apply to that respondent. Data values that are specified as user-missing are flagged for special treatment and are excluded from most calculations. To declare the codes that you use for your data. Click on the grey button with three dots below the heading (Missing) to display the Missing Values dialogue box: Select Discrete missing values. You can enter up to three discrete (individual) missing values codes, or a range plus one optional discrete missing value. Ranges can be specified only for numeric variables. You cannot define missing values for long text variables that are longer than eight characters. Enter the missing number in the text. Ensure that the number you enter is not valid in your data set. You cannot exceed 255 characters. Click on the spinner (arrowhead up/down) to increase or decrease the numbers. Page 20 An Introduction to IBM SPSS Statistics 19

25 Click on the arrowhead to display a dropdown list. Select the required alignment. The default is right for numeric values and left for string values. The alignment only displays in the Data View. You can choose from three different levels of measurements. Click on the arrowhead to display a dropdown list. Select the required option. Some dialogs support predefined roles that can be used to pre-select variables for analysis. When you open one of these dialogs, variables that meet the role requirements will be automatically displayed in the destination list(s). Available roles are: Input. The variable will be used as an input (e.g., predictor, independent variable). Target. The variable will be used as an output or target (e.g., dependent variable). Both. The variable will be used as both input and output. None. The variable has no role assignment. Partition. The variable will be used to partition the data into separate samples for training, testing, and validation. Split. Included for round-trip compatibility with IBM SPSS Statistics Modeler. Variables with this role are not used as split-file variables in IBM SPSS Statistics. By default, all variables are assigned the Input role. This includes data from external file formats and data files from versions of SPSS Statistics prior to version 18. Role assignment only affects dialogs that support role assignment. It has no effect on command syntax. (This information on Role was taken from the IBM SPSS Statistics help topics) An Introduction to IBM SPSS Statistics 19 Page 21

26 Working in Data View The Data view is used to enter data after you have defined the variable names in the Variable View window. In Data view if you place the mouse pointer over one of the variable names (column heading), a more descriptive variable label is displayed (only if you have defined a label for that variable, see section above Defining Variable names). By default, the actual data values are displayed in the cells. To make it easier to interpret the responses, you can switch the view. To switch the view from values to labels: Click on the View menu, select Value Labels, alternatively, Click on the Value Labels button on the toolbar. Editing Values and Variable Names To edit a value or variable name in the Data view: Double-click in the cell that contains the value or variable name. Type the relevant information. Press Enter (or move the cursor to another cell) to display the new value. Inserting Cases and Variables To insert cases (rows) in data view window: Place the cursor where you want to insert the case(s): Click on the Edit menu, select Insert Cases, alternatively, Click on the Insert Cases button on the toolbar. To insert variable name(s) in the variable view window: Place the cursor where you want to insert the variable name(s): Page 22 An Introduction to IBM SPSS Statistics 19

27 Click on the Edit menu, select Insert Variables, alternatively, Click on the Insert Variables button on the toolbar. Deleting Cases and Variable Names To delete cases in the data view window: Click on the row number on the left of the case you want to delete, to highlight the entire row. Click on the Edit menu, select Clear to delete the entire row. To delete variable name and content in the variable view window: Click on the column heading to highlight the entire column that contains the variable you want to delete Click on the Edit menu, select Clear to delete the entire column. Splitter control The splitter control is a quick and easy way to manage data sets that are very wide and long. You can split the window vertically and horizontally into two panes and control each pane separately. It is also useful for copying and moving data between parts of a long data set. To set the splitter control: Click on the Window menu, select Split. The horizontal and vertical splitter bars appears on the screen: You can change the position of the vertical or horizontal bar, e.g. if you place the cursor on the horizontal bar the cursor changes to An Introduction to IBM SPSS Statistics 19 Page 23

28 a drag it to the position you want. If you only want to use one bar, double click on the one you don t want to use to hide it. Notice when you use the scroll bar to scroll through the data you can view two parts of your data set simultaneously. To remove the split, click on the Window menu, select Remove Split. Saving a Data File To save a data file: Click on the File menu and select one of the save options: Save - if you select this option and the file has no name, the Save Data As dialogue box appears, enter the file name for the new data file, if the file has already been saved, selecting this option will update the file. Click on the OK button to save the file. Save As - if you select this option, the Save Data As dialogue box appears, enter the file name for the new data file and click on the OK button to save the file. SPSS add.sav extension to the file name. Opening a Data file There are several ways of opening a data file: Click on the Open button on the toolbar or File menu. Select Open Data Alternatively, when you start IBM SPSS Statistics you can select the Open Existing Data Source option on the IBM SPSS Statistics dialogue box. The Open Data dialogue box appears find the required file and click OK. Running an Analysis The Analyze menu contains a variety general reporting and statistical analysis categories. In this course we will only focus on some of the descriptive statistic functions such as Frequencies, Descriptives and Crosstabs. Page 24 An Introduction to IBM SPSS Statistics 19

29 Selecting Cases You can use the Select Cases function to perform an analysis on a subset of cases, for example, suppose we want to find out which eye colour is more common in female respondent. We can use the Select Cases function to deselect the male, and then run the analysis to find out the most common eye colour in female respondent. To select a subset of cases: Click on the Data menu and choose Select Cases or click on the Select Cases button Cases dialogue box appears: on the toolbar, the Select An icon next to each variable on the left provides information about the data type and level of measurements Measurement Level Scale (continuous) Data Type Numeric String Date Time n/a Ordinal Nominal To view the full description of a variable label, place the mouse pointer on the label. An Introduction to IBM SPSS Statistics 19 Page 25

30 You can also get additional labelling information by right clicking on any one of the variable name in the list. Under Select at the top right of the Select Cases dialogue box, All cases is the default. Click on the radio button to select the If condition is satisfied option, then click on the If button Cases: If dialogue box: to display the Select Page 26 An Introduction to IBM SPSS Statistics 19

31 Enter the condition in the text box on the right e.g. Gender = 2 to select the female respondent. (In the data set female was coded as 2). Click on the Continue button at the bottom of the Select Cases: If dialogue box. Click on the OK button on the Select Cases dialogue box. Notice the row numbers on the left of your data set has a line through the number; these are the cases that have been deselected. A filter column is inserted in your data set which displays the selected and unselected cases. Notice at the bottom right of the status bar Filter On appears. To unselect the cases, open the Select Cases dialogue box. Click on the Data menu and choose Select Cases or click on the Select Cases button Cases dialogue box appears). on the toolbar (the Select Click on the radio button to the left of the All cases option to restore the entire data file to its original form. Under Output at the bottom of the Select Cases dialogue box, Filter out unselected cases is selected; this means cases are only temporarily deselected. An Introduction to IBM SPSS Statistics 19 Page 27

32 Creating a Frequency table To create a simple frequency table: Click on the Analyze menu, select Descriptive Statistics, then Frequencies The Frequencies dialogue box appears: Select the variable(s) that you want to use to create the groups from the source list by double-clicking on it to move it into the Variable(s) list on the right, alternatively, click on the arrow button Select the variable(s) you want, e.g. eye colour and gender Click on the button with the arrow to move the variable into the Variable(s) list box. Click on the OK button to run the procedure. Page 28 An Introduction to IBM SPSS Statistics 19

33 IBM SPSS Statistics Viewer Working with SPSS Output The results are display in the IBM SPSS Statistics Viewer window. You can quickly go to any item in the Viewer by selecting it in the Outline pane The frequency table shows the frequencies for each eye colour Split file You can split your data file into separate groups for analysis e.g. its equivalent to separately selecting each category of gender and then running the descriptives command. It would allow you to perform a particular analysis base on the gender; you may want to look at the average height of males versus the average height of females. To split the data file: Click on the Data menu, select Split File... or click on the Split File button on the toolbar. An Introduction to IBM SPSS Statistics 19 Page 29

34 The Split File dialogue box appears: Analyze all cases, do not create groups is the default. Select Compare groups. Select the variable(s) that you want to use to create the groups from the source list by double-clicking on it to move it into the Variable(s) list on the right, alternatively, click on the arrow button Select the variable(s) you want, e.g. gender (the variable should be categorical). Click on the button with the arrow to move the variable into the Variable(s) list box. Click on the OK button to run the procedure. Notice the gender column is grouped by male and female and at the bottom right of the status bar Split File On is displayed. To turn off Split file, click on the Data menu, select Split file, then select Click on the OK button. on the Split File dialogue box. Page 30 An Introduction to IBM SPSS Statistics 19

35 Creating a Descriptives table To calculate a basic Descriptives statistic: Click on the Analyze menu, select Descriptives Statistics, then Descriptives, the Descriptives dialogue box appears: Select the variable(s) that you want to use to create the groups from the source list by double-clicking on it to move it into the Variable(s) list on the right, alternatively, click on the arrow button Select the variable(s) you want e.g. Height. Click on the button with the arrow to move the variable into the Variable(s): list box. Click on the Options button the Descriptives: Options dialogue box appears: An Introduction to IBM SPSS Statistics 19 Page 31

36 Select the required option(s), by default the Mean, Std. deviation, Minimum and Maximum are selected. Click on the OK button on the Descriptives dialogue box to run the procedure. The table is generated on the Output viewer: Average height of male Average height of female Recoding The Recoding function is useful for combining categories; you can reassign the values of existing variables into a new value. However, you cannot recode numeric and string variables together. Recoding can be done in three different ways: We are going to use the Recode into Different Variables function. Suppose we want to find out if more males or more females like chocolate. We could recode chocolate into two groups: Group 1 = dislike chocolate Group 2 = like chocolate Our old and new values are as follows: Old values New values 1 = dislike chocolate 1 Group 1 2 = a little bit 3 = quite a lot 4 = very much Group 2 To recode into different variables: Click on the Transform menu. Page 32 An Introduction to IBM SPSS Statistics 19

37 Select Recode into Different Variables The Recode into Different Variables dialogue box appears: Select the variable you want to recode from the source list by double-clicking on it to move it into the Numeric Variable Output Variable: text box on the right, alternatively, click on the arrow button (this is the original variable name). Under Output Variable, enter a name for the new variable (this is the variable that will contain the recoded data). Under Label: enter a description for the new recoded variable. Click on the Change button to insert the name into Numeric Variable Output Variable: text box. Click on the Old and New Values button to display the Recode into Different Variables: Old and New Values dialogue box: The Recode into Different Variables: Old and New Values dialogue box is used for defining the old and new values. On the left is the Old value and on the right is the New Value. Under Old Value select Value and type 1 in the value in the text box (this is your original code). An Introduction to IBM SPSS Statistics 19 Page 33

38 Under New Value, select Value and type 1 in the Value text box (this will be the new code). Click on the Add button to list the recode of the original code into the Old New text box. To add another group, Under Old Value click on Range: in the range text boxes enter the old code, 2 and 4 (these were your original codes). Under New Value, select Value: and type 2 in the Value text box (this will be the new code). Click on the Add button to list the recode of the original codes in the Old New text box. Click on the Continue button at the bottom of the Recode into Different Variables: Old and New Values dialogue box, to go back to the Recode into Different Variables dialogue box: Click on the OK button to perform the recode, (a new column is inserted at the end of your data set). A new variable column is inserted in the data set (it s the last column) and in variable view the new variable is inserted (it s the last row) you can define the new variable, e.g. 1 = dislike and 2 = like. Cross Tabulation You can use the Crosstabs function to explore the relationship between two categorical variables, e.g. we are going to use the recoded variable above to run a cross tabulation table to find out if more males or more females like chocolate. To create a cross tabulation table: Click on the Analyze menu, select Descriptive Statistics then select Crosstabs the Crosstabs dialogue box appears: Page 34 An Introduction to IBM SPSS Statistics 19

39 In the Source Variable list on the left select the required variable for Row(s), Column(s) and if required Layer 1 of 1 then click on the arrow to copy the variable into the relevant text box, e.g. add the Recoded variable in the Row(s) and the Gender in the Column(s). Click on the OK button to generate the cross tabulation table on the Output viewer as shown below: The table reports that one male and one female dislike chocolates. 10 male like chocolates and 14 female like chocolates. Compute function You can use the compute function to create a new variable - let s say you want to increase the salary by 2.5%: To enter a calculation that will increase the salary by 2.5%: Click on the Transform menu Select Compute Variable to display the Compute Variable dialogue box: In the Target Variable: text box, enter a new name for the new variable, e.g. IncreaseSalary. An Introduction to IBM SPSS Statistics 19 Page 35

40 In the Source Variable list on the left select the required variable, e.g. Salary and then click on the arrow to copy the variable into the Numeric Expression: text box. You can use the Calculator key pad or the keyboard to enter a formula that will calculate the salary. You can also use pre-defined functions from the Function group list on the right of the Compute Variable dialogue box. Click on the OK button to calculate the new variable. The new variable is inserted to the right of your data set in the Data view window, (it s the last column) and also (in the last row) in the Variable view window. Creating Charts Information can be displayed graphically by using the graph function. Graphs can also be requested at the same time when running an analysis. However, the graph facility provides a number of easy-to-follow steps when creating a chart. We are going to create a pie chart. Legacy Dialogs To create a pie chart using the Legacy Dialogs function: Click on the Graph menu, select Legacy Dialogs. The Pie Charts dialogue box appears, select the Summaries of Groups and Cases and click on the Define button. The Define Pie:Summaries for Groups and Cases dialogue box appears: Page 36 An Introduction to IBM SPSS Statistics 19

41 Enter the required variable(s) in the text box on the right. You can add a title to your chart by clicking on the Titles button at the top right of the Define Pie: Summaries for Groups of Cases dialogue box. Click on the OK button to generate the pie chart in the Output Viewer window. To edit the pie chart double-click on it to open it in the Chart Editor window, then double-click again anywhere on the chart to open the Properties dialogue box. An Introduction to IBM SPSS Statistics 19 Page 37

42 Click on the File menu and select Close to close the Chart Editor to return to the SPSS Statistics Viewer. Chart Builder You can use the Chart Builder to build a chart from the pre-defined gallery chart. To build a bar chart: Click on the Graph menu, select Chart Builder..., the Chart Builder dialogue box appears, which you can use to help you to create descriptive value labels for categorical (nominal, ordinal) variables. Press OK to define your chart. Page 38 An Introduction to IBM SPSS Statistics 19

43 The Chart Builder dialogue box appears: Click on the Gallery button on the left of the Chart Builder dialogue box to display a list of pre-defined charts To start building your chart - under Choose from: click on the chart you want, e.g. Bar. If you want a description of the chart, place your mouse pointer over the chart icon. Drag the chart icon into the chart preview window that contains the following information: Drag Gallery chart here to use it as your starting point OR Click the Basic Elements tab to build a chart element by element. A sample bar chart is displayed without variables (This area allows you to preview how a chart will look while you build it) An Introduction to IBM SPSS Statistics 19 Page 39

44 Under Variables: click on the required variable from the source list and drag-and-drop it on the X-Axis? box and click on another variable and drag-and-drop Y-Axis. If you make a mistake while building the chart, right click on the chart to get a short-cut menu and select undo option You can enter a title for your chart by clicking on the Titles/Footnotes tab at the bottom of the Chart Builder dialogue box. Select Title 1 a text box is displayed on the Element Properties dialogue box. Type the chart tile into the Contents text box and click on the Apply button. T1 is displayed as the title, the full title will appear when you generate the chart on the Output viewer Page 40 An Introduction to IBM SPSS Statistics 19

45 When you have finished adding the chart elements to the chart Click on the OK button to generate the chart on the Output Viewer Editing charts You can edit the chart within the chart builder window or the Output viewer window. To edit the chart: Double-click on the chart to open the Chart Editor To edit the chart element, click on it to select it Press the Esc key on the keyboard to deselect the element(s) An Introduction to IBM SPSS Statistics 19 Page 41

46 To delete a chart element, select it from the Edit Properties of list in the Element Properties dialogue box, and then click on the red X button on the right. Changing the chart colour To change the colour of the bar(s): Click on the chart bar, a rectangle appears around all of the bars To select an individual bar, click on it while all the other bars are selected, you can also select multiple bars by holding down the Ctrl key on the keyboard while you click on the bar The tabs in the Edit Properties tabs will change depending on the element you select in the Chart Editor Click on the Apply button Change the Y-axis scale To format numbers in the Y-axis scale: Select the Y-axis tick label Click on the Edit menu, or Ctrl T, select Properties to open the Properties window Click on the Number Format tab Click the Apply button Change the title To change the title: You can edit text directly on the chart Click on the title e.g. main title or Y-axis title to select it (the title text is rotated into a horizontal position, with a flashing red border) Types the required title and press Enter to exit the Edit mode Displaying data value labels To display data value labels: Open the Chart Editor Click on the Element menu, select Data Label The value is displayed on each bar Page 42 An Introduction to IBM SPSS Statistics 19

47 A Study of the Wonderful People Who Come on Research Skills Training Courses in the West Midlands Please complete the following questions by ticking the appropriate box(es) or writing brief information in the space provided when requested. (You do not have to tell the truth!) 1. What is your gender? Male 1 Female 2 2. What colour are your eyes? blue brown green grey other How tall are you? 180 cm 4. Which of the following best describes where you live? a city a town 2 the countryside don t know How far did you travel to get here today? 9km 6. How much do you like chocolate? not at all a little bit 2 quite a lot very much 7. What colour is your car? silver 1 black 2 white 3 green 4 blue 5 red 6 other 7 8. How satisfied are you with your job? very satisfied 1 fairly satisfied no opinion a little dissatisfied very dissatisfied If you could be any of the following, which would you choose to be? Prime Minister Road Sweeper 2 Teacher 3 Call Centre Op How much are you paid per annum? What is the post code of your place of work? B2 5JS 12. Where did you go for your last holiday? UK Europe Outside Europe Other Thank you for completing this questionnaire. Your responses will remain totally anonymous