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SPSS Lecture_1 [Autosaved].pptx
- 1. College of HealthSciences Department of Public Health Leta Adugna (BSc, MPH/Epidemiology) November 5, 2023 1
- 2. Objectives • At theend of this lecture, students are expected to • Identify the different windows in SPSS • Define variables, enter, manipulate, and save data • Manage and analyze data, produce graphs • Interpret the results of data analysis using different assumptions November 5, 2023 2
- 3. Introduction to SPSS •SPSS was originally launched in 1968 by SPSS Inc., and was later acquired by IBM in 2009. • Distributed for data management and statistical analysis. • The SPSS software package is continually being updated & improved. • The data from other software can be exported to SPSS for detailed analysis. November 5, 2023 3
- 4. Introduction to SPSS…Window name (Title bar) Menu bar Workflow tool bar November 5, 2023 4
- 5. SPSS Windows • Thereare three main and separate windows: The Data Editor window The Output (Viewer) window The Syntax Editor window November 5, 2023 5
- 6. 1. Data editorwindow • It is the view where we see our data • It is useful to see and manipulate the data • It has *.sav extension • It has two views: Data view and Variable view • Views can be exchanged by clicking the view we desire at the left most lower side of the data editor. November 5, 2023 6
- 7. 1. Data editorwindow… Variable view Data view November 5, 2023 7
- 8. 1. Data editorwindow… 1. Data view • Simple observation of: •Variables name •Variables value • We are able to edit directly the values of variables. • Data can be entered when SPSS is in data view • Data quality? November 5, 2023 8
- 9. 1. Data editorwindow… Data view… Row (case) • A horizontally recorded Single study subject’s information. Column (variable) • A vertically recorded single Variable’s value across all study subjects. November 5, 2023 9
- 10. 1. Data editorwindow… 2. Variable view • It is important to create new variables in SPSS • It is by writing name of variable, type of variable, its label and its value November 5, 2023 10
- 11. 2. Variable view… 1.Name of variables • Must be unique • Must begin with a letter or one of the symbols @, #, or $ • Only letters, numbers, the period (.), underscore (_), and the $, #, and @ symbols can be used within variable names • Spaces are not allowed within variable names • Name of variable should not start using number • Example: Agegroup (correct) vs age group (incorrect) p01age (correct) vs 01age (incorrect) November 5, 2023 11
- 12. 2. Variable Type 1.Numeric: for countable (quantitative) only accepting numerical (coding of categorical variables is possible) 2. Date: characteristics it can use different styles of dates 3. String: if we interested in words. (alphanumeric variables or character variables). 2. Variable view… November 5, 2023 12
- 13. 2. Variable view… 3.Width • Allow number of characters of continuous variable. • If numeric type of variable, it will ask to choose number of widths and decimals (as a default the width comes 8 and decimals of 2). • If date type of variable, it may ask you to choose number of characteristics of the type of date. • If a categorical data with words, it will ask you to choose number of characteristics you wanted to add. November 5, 2023 13
- 14. 2. Variable view… 4.Decimals • Number of decimals • It has to be ≤16 • If it is date or string variable, it will not request you decimals 14
- 15. 2. Variable view… 5.Label of the variables • It’s detailed description of the variable name • You can write characters with spaces up to 256 characters November 5, 2023 15
- 16. 2. Variable view… 6.Values of the variable • It’s is the description of values of variables of categorical variables coded as quantitative. • Eg. ‘Sex’ (1. male, 2. female) ‘Residence’(1. urban, 2. rural) • For continuous variables, no value is needed to be coded November 5, 2023 16
- 17. • Defining thevalue labels • Click the cell in the values column as shown below • For the value, and the label, you can put up to 60 characters. • After defining the values click add and click OK. 2. Variable view… click 1. Write the value first 2. Write its meaning 3. Click “add” to pass 4. Click “ok” to finish 17
- 18. 2. Variable view… 7.Missing • Specify what is to be entered for a value that is missing for a variable. • Arise when no data value is saved for the variable in observation. click November 5, 2023 18
- 19. 2. Variable view… 8.Columns • Determine the space of a column of a variable • Note that this is not the same as the number of digits displayed for each value. • This simply refers to the width of the actual column in the spreadsheet. November 5, 2023 19
- 20. 2. Variable view… 9.Align • The alignment of content in the cells of the SPSS Data View spreadsheet. • Options include • Left-justified, • Right-justified, or • Center-justified. November 5, 2023 20
- 21. 2. Variable view… 10.MEASURE • The level of measurement for the variable (e.g., nominal, ordinal, or scale). • Nominal for categorical, ordinal for ordered type and scale for numerical. click November 5, 2023 21
- 22. 2. Variable view… 11.ROLE • The role that a variable will play in your analyses (i.e., independent variable, dependent variable, both indpt and dpt). • Input: The variable will be used as a independent variable (the default assignment for variables). • Target: The variable will be used as an dependent variable. • Both: The variable will be used as both indpt and dpt. • None: The variable has no role. • Partition: The variable will partition the data into separate samples. • Split: Used with the IBM® SPSS® Modeler (not IBM® SPSS® Statistics). click November 5, 2023 22
- 23. Saving data filein SPSS 1. File 2. Save as 3. By clicking HERE you can choose where to save your file. 4. By typing HERE you can give your file a name. 5. By clicking HERE you can choose a type of your data file. 6. Click here to save. November 5, 2023 23
- 24. 2. The Viewerwindow • The Viewer window displays all •Statistical results, •Tables, and •Charts •Commands…etc. •It has *.spv extension November 5, 2023 24
- 25. 2. The Viewerwindow… Output in detail Output in outline Title bar and menu bar in output window November 5, 2023 25
- 26. 3. The SyntaxEditor • It is the window in which SPSS commands can be typed and submitted for processing. • Commands saved in files can be opened in a syntax Editor • Window for processing. • It has *.sps extension November 5, 2023 26
- 27. 3. The SyntaxEditor… Program with a command Syntax menu Clicking here will execute a command November 5, 2023 27
- 28. • Once asyntax is written, we are able to execute it. • In excuting a syntax we are able to do the whole program as whole or by selecting part of the syntax • To do the whole syntax, select the ‘run’ from the pulldown menu of the syntax and select ‘all’ • To excute part of the syntax, shade it and run the file 3. The Syntax Editor… November 5, 2023 28
- 29. Opening an existingdata file • From already entered and saved data file: • In data editor window, • Choose the file type, and then browse and select your file so it appears by file name. File Open Data November 5, 2023 29
- 30. Opening an existingdata file… By clicking the file type, you are able to find the type of extension By clicking the here, you are able to find where your file is. you can search your file name by typing here. November 5, 2023 30
- 31. Data •Merge files •Sort cases •Splitfile •Select cases Transform •Compute •Recode Analysis •Descriptive Stat.. •Compare means •Correlate •Regression •Survival Graphs •Bar •Histogram •Scatter plot •Line •Pie •Box plot SPSS Data Management and Interpretations November 5, 2023 31
- 32. Data • Merge files •Sort cases • Split files • Select cases November 5, 2023 32
- 33. 1. Merge files •Two data files are merged (mixed) together November 5, 2023 33
- 34. A. Merging toadd cases (rows) • Here two different data files will be merged • To merge data the two files should have variables of the same characteristics on: • Name of variable • Type of variable • Width and decimals the variable has • Usually such merging is possible if we use similar template during data entry. • If there is slight difference in characteristics of a variable then merging for that variable will be difficult. November 5, 2023 34
- 35. A. Merging toadd cases (rows)… Steps 1. Open one of the two files (the file that you assume will be the first file) 2. From the pull down menu click “Data” and go down to select “Merge files” 3. From the “Merge files” select “add cases” Data Merge files Add cases November 5, 2023 35
- 36. • Select thedata file you wanted through the Browser to merge and click the Continue Select here 2nd Click here, to select file November 5, 2023 36
- 37. A. Merging toadd cases (rows)… You will find two windows 1. Unpaired variables • list of variables that are not matched thus could not be included in the new file • If there is slight difference in the characteristics of variables it will be categorized to this window * for variables that come from the opened file + for variables that come from the new file November 5, 2023 37
- 38. Con't … Unpaired variables November5, 2023 38
- 39. A. Merging toadd cases (rows)… 2. Variables in the new working file • List of variables that could be merged to the file • If all variables are found in this window, we could click “Ok” and we could have a new file that needs saving, and we should save it for further analysis. November 5, 2023 39 Variables in the new working file
- 40. B. Merging toadd variables (columns) • It is used when we want to add certain variables of a file from other database. • Here a variable having a common identity of cases is needed. • One or more variables are added to each cases of the file. November 5, 2023 40
- 41. Steps Data Merge files Add variables 1. Click browse, to select file November 5, 2023 41
- 42. • A windowthat asks you browse to add file containing the variable you need comes 2. select “file name”, then, 3. click “open” 4. click “continue” 5. click “OK” November 5, 2023 42
- 43. You will findtwo windows 1. Excluded variables • list of variables that would be excluded from the working file are included • Variables found in common are also listed here, thus the common identity also will be found here * for variables that come from the opened file + for variables that come from the new file 2. Variables in the new working data file • List of variables that would be found in the new file • If all variables needed to the original file are included, process of merging will be started. November 5, 2023 43
- 44. 2. Sort • Sortingis useful in cleaning data. • When you sort ascending or descending, you can find ‘missing data’, ‘unknown (unexpected)’ data and ‘outliers’. • If you find such cases, you can re-check with hard data for possible correction. • It is also useful during merging (especially when you are adding variables). November 5, 2023 44
- 45. Two methods tosort data A. Using menu bar Data Sort cases 1st select the variable 3rd select ascending or descending sorting 2nd click here to pass into sort by November 5, 2023 45
- 46. B. Right clicking •Open “data view” format of the SPSS. • Go to the variable name and do a right click. • And select ascending or descending sorting as you wish. • The outcome is then displayed in the Data editor, on “data view”. November 5, 2023 46
- 47. 3. Split file •It is used to do analysis by stratification • Data is stratified by the variable selected for splitting. • Out come (result) of the planned analysis is displayed by stratification (i.e. result for each value stratified is given separately • Eg: if data is split by sex, then any analysis done will be displayed for males and for females November 5, 2023 47
- 48. Steps 1. From themenu bar click “Data” and go down to select “Split file” Data Split file November 5, 2023 48
- 49. 1st Select “Organizeoutput by groups” or “compare groups” 2nd Select the variable you wanted to split your file November 5, 2023 49
- 50. 3rd Click thearrow to pass To “Groups based on:” Finally, click Ok Then do any analysis you wanted to perform November 5, 2023 50
- 51. 4. Select cases •It is useful when you want to analyze data among certain category of a variable (conditionally selected data). • E.g.: You can analyze data only among female population. • It can also be used to select study subjects from sample frame (Simple random sampling). • It can also used to select certain range of a population in sequence, etc November 5, 2023 51
- 52. Steps I) Conditional selection •From the menu bar click “Data” and go down to select “Select cases” Data Select cases November 5, 2023 52
- 53. 1st Select “Ifcondition is satisfied” 2nd Click “if” November 5, 2023 53
- 54. 3rd. 1st Selectthe variable you wanted to select 4th. 2nd Click the arrow to pass the variable” Do the function you wanted to select November 5, 2023 54
- 55. Variable Function Click the“continue” November 5, 2023 55
- 56. You can choose theoutput option here Finally, click “OK” Any analysis done will be on these selected category fulfilling the criteria of selection November 5, 2023 56
- 57. II) Simple randomsample selection • There is a need of a list of the population (Sampling frame) • From the pull down menu click “Data” and go down to select “Select cases” Data Select cases November 5, 2023 57
- 58. 1st Select “Random sampleof cases” 2nd Click “Sample” November 5, 2023 58
- 59. 1st Click “Exactly” 2ndwrite the desired sample size 3rd write the total population in the list Finally, click continue November 5, 2023 59
- 60. Output options Finally, click“OK” List of the sample is finally created November 5, 2023 60
- 61. Thank you! November 5,2023 61