Hướng dẫn sử dụng SPSS

A Step-by-Step Guide to Analysis and Interpretotion Brian C Cronk I ll L :,- Choosing the Appropriafe Sfafistical lesf Ytrh.t b Yq I*l QraJoi? Dtfbsr h ProportdE Mo.s Tha lnd€Fndont Varidl6 lhre Thsn L€wls of Indop€nddtt Varisd€ lldr Tho L6Eb d li(bsxlq* Vdidb f'bre Tha 'l Indopadqrl Vdbue '| Ind.Fddrt Vri*b NOTE:Relevant sectionnumbers are givenin parentheses Forinstance, '(6.9)"refersyouto Section6.9in Chapter6 fro.! Itn I l.doFfihnt Vdi.bb I Notice SPSSis a registeredtrademarkof SPSS,Inc Screenimages@ by SPSS,Inc and MicrosoftCorporation.Usedwith permission This book is not approvedor sponsoredby SPSS "PyrczakPublishing"is an imprintof FredPyrczak,Publisher, A CaliforniaCorporation Althoughtheauthorandpublisherhavemadeeveryeffortto ensuretheaccuracyand for no responsibility completeness of informationcontainedin thisbook,we assume herein.Any slightsof people, errors,inaccuracies, omissions, or anyinconsistency places,or organizations areunintentional ProjectDirector:MonicaLopez ConsultingEditors:GeorgeBumrss,JoseL Galvan,MatthewGiblin,DeborahM Oh, JackPetit.andRichardRasor providedby CherylAlcorn,RandallR Bruce,KarenM Disner, Editdrialassistance BrendaKoplin,EricaSimmons,andSharonYoung Coverdesignby RobertKibler andLarryNichols Printedin theUnitedStates of Americaby Malloy,Inc All rights Publisher Copyright@2008,2006,2004,2002,1999 by FredPyrczak, in anyform or by any or transmitted reserved No portionof thisbookmaybe reproduced meanswithouttheprior writtenpermission of thepublisher r s B N l -8 s8 -79 -5 Tableof Contents Introduction to theFifth Edition v What'sNew? Audience Organization SPSSVersions Availabilityof SPSS Conventions Screenshots PracticeExercises Acknowledgments'/ ChapterI Ll t.2 1.3 1.4 1.5 1.6 1.7 Chapter2 2.1 ') ') Chapter3 3.1 3.2 3.3 3.4 3.5 Chapter4 4.1 4.2 4.3 4.4 4.5 4.6 Chapter5 5.1 5.2 5.3 5.4 v v v vi vi vi vi vii vii GettingStarted I StartingSPSS EnteringData DefiningVariables LoadingandSavingDataFiles RunningYour FirstAnalysis ExaminingandPrintingOutputFiles Modi$ing DataFiles I I EnteringandModifyingData VariablesandDataRepresentation Transformation andSelection of Data ll t2 Descriptive Statistics l7 Frequency Distributions andpercentileRanksfor a singlevariable Frequency Distributions andpercentileRanksfor Multille variables Measuresof CentralTendencyandMeasuresof Dispersion for a SingleGroup Measures of CentralTendency andMeasures of Dispersion for MultipleGroups StandardScores t7 20 ll 2l 24 )7 GraphingData 29 GraphingBasics TheNew SPSSChartBuilder Bar Charts,Pie Charts,andHistograms Scatterplots AdvancedBarCharts EditingSPSSGraphs 29 29 3l 33 36 39 Predictionand Association 4l PearsonCorrelation Coeffi cient SpearmanCorrelation Coeffi cient Simple Linear Regression Multiple Linear Regression 4l 43 45 49 u, Chapter6 Parametric InferentialStatistics 53 Reviewof BasicHypothesis Testing Single-Sample t Test Independent-Samples I Test Paired-Samples t Test One-WayANOVA FactorialANOVA Repeated-Measures ANOVA Mixed-Design ANOVA Analysisof Covariance MultivariateAnalysisof Variance(MANOVA) 53 )) 58 6l 65 69 72 75 79 8l Chapter7 Nonparametric InferentialStatistics 85 7.1 7.2 7.3 7.4 7.5 7.6 Chi-Square Goodness of Fit Chi-SquareTestof Independence Mann-Whitney UTest WilcoxonTest Kruskal-Wallis,F/Test FriedmanTest 85 87 90 93 95 97 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10 Chapter8 8.1 8.2 8.3 8.4 TestConstruction 99 Item-TotalAnalysis Cronbach's Alpha Test-RetestReliability Criterion-Related Validiw 99 100 l0l t02 AppendixA Effect Size 103 AppendixB PracticeExerciseDataSets r 09 PracticeDataSet I PracticeDataSet2 PracticeDataSet3 109 ll0 ll0 AppendixC Glossary lt3 AppendixD SampleDataFilesUsedin Text tt7 n7 COINS.sav GRADES.sav HEIGHT.sav QUESTIONS.sav RACE.sav SAMPLE.sav SAT.sav OtherFiles l l7 l l7 n7 l18 l18 lt8 lt8 AppendixE Informationfor Usersof EarlierVersionsof SPSS l19 AppendixF GraphingDatawith SPSS13.0and 14.0 t2l tv ChapterI GettingStarted Section1.1 StartingSPSS ffi$ t't**** ffi c rrnoitllttt (- lhoari{irgqrory r,Crcrt*rsrcq.,y urhgDd.b6.Wbrd (i lpanrnaridirgdataura f- Dml*ro* fe tf*E h lholifrra Startup proceduresfor SPSS will differ slightly, dependingon the exact configurationof the machine on which it is installed.On most computers,you can start SPSS by clicking on Start, then clicking on Programs, then on SPSS On many installations,there will be an SPSSicon on the desktopthat you can double-click to start the program When SPSS is started,you may be presentedwith the dialog box to the left, depending on the optionsyour systemadministratorselected for your version of the program If you have the dialog box, click Type in data and OK, which will presenta blank data window.' If you were not presentedwith the dialog box to the left, SPSSshould open automatically with a blank data window The data window and the output window provide the basic interface for SPSS A blank data window is shownbelow Section1.2 EnteringData One of the keys to success with SPSSis knowing how it stores :g H*n-g:fH"gxr }rry".** r! *9*_r1_*9lt and uses your data To illustrate the rtlxlel&l *'.1 rtl ale| lgj'Slfil Hl*lml sl el*l I basics of data entry with SPSS,we will useExample1.2.1 Example 1.2.1 A surveywas given to several students from four different classes (Tues/Thurs momings, Tues/Thurs afternoons, Mon/Wed/Fri mornings, and afternoons) Mon/Wed/Fri The students were asked ' Items that appearin the glossaryare presentedin bold Italics areusedto indicatemenu items ChapterI GeningStarted whether or not they were "morning people" and whether or not they worked This survey also asked for their final grade in the class (100% being the highest gade possible).The responsesheetsfrom two studentsarepresentedbelow: Response SheetI ID: Dayof class: Classtime: Are you a morningperson? Finalgradein class: Do youwork outsideschool? 4593 MWF Morning Yes X TTh X Aftemoon X No 8s% Part{ime Full-time XNo Response Sheet2 ID: Dayof class: Classtime: Are you a morningperson? Finalgradein class: Do vou work outsideschool? l90l x MwF X Morning X Yes 83% Full-time No _ - TTh Afternoon No X Part-time Our goal is to enterthe data from the two studentsinto SPSSfor use in future analyses The first stepis to determinethe variablesthatneedto be entered.Any informaExample tion that can vary amongparticipantsis a variablethat needsto be considered 1.2.2liststhevariables we will use Example1.2.2 ID Dayof class Classtime Morningperson Finalgrade Whetheror not the studentworksoutsideschool particivariablesandrowsrepresent In the SPSSdata window,columnsrepresent (variables) rows and two pants.Therefore,we will be creatinga datafile with six columns (students/participants) Section1.3 Defining Variables Beforewe can enterany data,we must first entersomebasicinformationabout eachvariableinto SPSS.For instance, variablesmustfirst be givennamesthat: o beginwith a letter; o not containa space Chapter I Getting Started Thus, the variable name "Q7" is acceptable,while the variable name "7Q" is not Similarly, the variable name "PRE_TEST" is acceptable, but the variable name "PRE TEST" is not Capitalizationdoes not matter, but variable namesare capitalizedin this text to make it clear when we are referring to a variable name, even if the variable name is not necessarilycapitalizedin screenshots To define a variable.click on the Variable View tab at thebottomofthema inscre e n Th is wills h o wy o u t h e V a ri-@ able View window To return to the Data View window click on the Data View tab Fb m u9* o*.*Trqll t!-.G q".E u?x !!p_Ip ,'lul*lEll r"l*l ulhl **l {,lrl EiliEltfil_sJ elrl l lt-*l*lr"$,c"x.l From the Variable View screen,SPSSallows you to createand edit all of the variables in your data file Each column representssome property of a variable, and each row representsa variable All variablesmust be given a name To that, click on the first empty cell in the Name column and type a valid SPSSvariable name The program will then fill in default valuesfor most of the other properties One usefulfunctionof SPSSis the ability to definevariableand value labels.Variable labels allow you to associatea descriptionwith each variable.Thesedescriptionscan describethe variablesthemselvesor the valuesof the variables Value labelsallow you to associatea descriptionwith eachvalue of a variable.For example,for most procedures,SPSSrequiresnumerical values.Thus, for data such as the day of the class (i.e., Mon/Wed/Fri and Tues/Thurs),we need to first code the values as numbers.We can assignthe number I to Mon/Wed/Friand the number2to Tues/Thurs To help us keep track of the numberswe have assignedto the values,we use value labels To assignvalue labels,click in the cell you want to assignvaluesto in the Values column This will bring up a small gray button (seeanow, below at left) Click on that button to bring up the Value Labelsdialog box When you enter a iv*rl** v& 12 -Jil value label, you must click L.b.f ll6rhl| s*l !!+ | Add after eachentry This will J::::*.-,.Tl mOVe the value and itS associated label into the bottom section of the window When all labels have been added, click OK to return to the Variable View window ChapterI Gening Starred In additionto namingand labelingthe variable,you havethe option of definingthe variabletype To so, simply click on the Type, Width,or Decimals columns in the Variable View window The default value is a numeric field that is eight digits wide with two decimalplacesdisplayed.If your dataare more than eight digits to the left of the decimal place,they will be displayedin scientificnotation(e.g.,the number2,000,000,000 will be displayedas 2.00E+09).'SPSSmaintainsaccuracybeyondtwo decimalplaces,but all output will be roundedto two decimal placesunlessotherwiseindicatedin the Decimals column In our example,we will be usingnumericvariableswith all of the defaultvalues Practice Exercise Createa data file for the six variablesand two samplestudentspresentedin Example 1.2.1.Name your variables:ID, DAY, TIME, MORNING, GRADE, and WORK You should code DAY as I : Mon/Wed/Fri,2 = Tues/Thurs.Code TIME as I : morning, : afternoon.CodeMORNING as = No, I : Yes Code WORK as 0: No, I : Part-Time,2 : Full-Time Be sure you enter value labels for the different variables.Note that because value labelsare not appropriatefor ID and GRADE, theseare not coded.When done,your Variable View window should look like the screenshotbelow: J -rtrr,d r9"o'ldq${:ilpt"?- "*- ? {!,_q, ru.g Click on the Data View tab to open the data-entryscreen.Enter data horizontally, beginningwith the first student'sID number.Enter the code for eachvariable in the appropriate column; to enterthe GRADE variablevalue,enterthe student'sclassgrade F.E*UaUar Qgtr Irrddn An hna gnphr Ufrrs Hhdow E* ulFId't Al 'r i-l-Etetmt lr*lEl&lr6lgl ot olrt' otttr *lgl dJl blbl slglglqjglej Dependingupon your versionof SPSS,it may be displayedas 2.08 + 009 Chapter I Getting Started Thepreviousdata window canbe changedto look insteadlike the screenshot bel*.bv clickingon the ValueLabelsicon(seeanow).In this case,the cellsdisplayvalue labelsratherthanthe corresponding codes.If datais enteredin this mode,it is not necessaryto entercodes,asclickingthebuttonwhichappearsin eachcell asthe cell is selected will presenta drop-downlist of thepredefined lablis You may useeithermethod,according to yourpreference : [[o|vrwl vrkQ!9try / )1 *rn*to*u*J . Instead of clicking the Value Labels icon, you may optionallytogglebetweenviews by clicking valueLaiels under the Viewmenu tu l{il Ddr lrm#m ,t Anrfrrr Cr6l! ,t1 r ti il 'i Section1.4 Loading and SavingData Files Onceyou haveenteredyour data,you will need to saveit with a uniquenamefor later useso that you canretrieveit whennecessary Loadingand savingSpSSdatafiles worksin the sameway as most Windows-based software.Underthe File menu, there are Open, Save, and Save As commands.SPSSdata files have a ,.sav" extension which is addedby defaultto the end of the filename ThistellsWindowsthatthefile is anSpSSdatafile I r lii |: H- Save Your Data When you save your data file (by clicking File, then clicking Save or SaveAs to specify a unique name),pay specialattentionto where you saveit trrtist systemsdefault to the.location.You will probably want to saveyour data on a floppy disk, cD-R, or removableUSB drive so that you can taie the file withvou Load YourData When you load your data (by clicking File, then clicking Open, thenData, or by clicking the open file folder icon), you get a similar window This window lists all files with the ".sav" extension.If you have trouble locating your saved file, make sure you are D{l lriifqffi looking in the right directory Appendix C Glossary Ordinal Scale A measurementscale where items are placed in mutually exclusive categories, in order Appropriate categories include "same," "less," and "more." Appropriatetransformationsinclude countingand sorting Outliers Extreme scoresin a distribution Scoresthat are very distant from the mean and the rest of the scoresin the distribution Output Window The SPSSwindow that containsthe resultsof an analysis.The left side summarizesthe resultsin an outline The right side containsthe actual results Percentiles(Percentile Ranks) A relative scorethat gives the percentageof subjectswho scoredat the samevalue or lower Pooled Standard Deviation A single value that representsthe standarddeviation of two groupsofscores Protected Dependent / Tests To preventthe inflation of a Type I error, the level needed to be significantis reducedwhen multipletestsare conducted Quartiles The points that define a distribution into four equal parts The scoresat the 25th,50th,and 75th percentileranks Random Assignment A procedurefor assigningsubjectsto conditionsin which each subjecthasan equalchanceofbeing assignedto any condition Range A measureof dispersionrepresentingthe number of points from the highestscore through the lowest score Ratio Scale A measurementscale where items are placed in mutually exclusive categories, with equal intervals between values, and a true zero Appropriate transformationsinclude counting,sorting,additiott/subtraction, and multiplication/division Reliability An indication of the consistencyof a scale A reliable scale is intemally consistentand stableover time Robust A test is said to be robust if it continuesto provide accurateresultseven after the violationof someassumptions Significance A difference is said to be significant if the probability of making a Type I error is less than the acceptedlimit (normally 5%) If a difference is significant, the null hypothesisis rejected Skew The extent to which a distribution is not symmetrical.Positive skew has outliers on the positive(right) sideof the distribution.Negativeskew hasoutlierson the negative(left) sideof the distribution Standard Deviation A measureof dispersion representinga special type of average deviation from the mean I 15 AppendixC Glossary Standard Error of Estimate.The equivalentof the standarddeviationfor a regression line with a standard line.The datapointswill be normallydistributedaroundthe regression deviationequalto the standarderrorof the estimate StandardNormal Distribution A normaldistributionwith a meanof 0.0 anda standard deviation of 1.0 String Variable A stringvariablecancontainlettersandnumbers.Numericvariablescan containonly numbers.Most SPSScommands will not functionwith stringvariables Temporal Stability This is achievedwhen reliability measureshave determinedthat scoresremainstableovermultipleadministrations of the instrument Tukey's HSD A post-hoccomparisonpurportedto reveal an "honestly significant difference"(HSD) erroneouslyrejectsthe null Type I Error A Type I error occurswhen the researcher hypothesis fails to rejectthe erroneously Type II Error A Type II erroroccurswhenthe researcher null hypothesis Valid Data.DatathatSPSSwill usein its analyses Validity An indicationof theaccuracyof a scale Variance.A measure deviation of dispersion equalto thesquaredstandard l16 AppendixD SampleDataFilesUsedin Text A varietyof smalldatafiles areusedin examplesthroughoutthis text Hereis a list of whereeachappears COINS.sav Variables: COINI COIN2 Enteredin Chapter7 GRADES.sav Variables: PRETEST MIDTERM FINAL INSTRUCT REQUIRED Enteredin Chapter6 HEIGHT.sav Variables: HEIGHT WEIGHT SEX Enteredin Chapter4 QUESTIONS.Sav Variables: Ql Q2 (recodedin Chapter2) Q3 TOTAL (addedin Chapter2) GROUP(addedin Chapter2) Enteredin Chapter2 Modifiedin Chapter2 tt7 AppendixD SampleDataFilesUsedin Text RACE.sav Variables: SHORT MEDIUM LONG EXPERIENCE Enteredin Chapter7 SAMPLE.sav Variables: ID DAY TIME MORNING GRADE WORK TRAINING (addedin Chapter1) Enteredin ChapterI Modifiedin ChapterI SAT.sav Variables: SAT GRE GROUP Enteredin Chapter6 Other Files For somepracticeexercises, seeAppendixB for neededdatasetsthatarenot usedin any otherexamplesin thetext l18 AppendixE Informationfor Users of EarlierVersionsof SPSS r{ ril Thereare a numberof differences betweenSPSS15.0and earlierversionsof the software.Fortunately,mostof themhavevery little impacton usersof this text In fact, mostusersof earlierversionswill be ableto successfully usethis text withoutneedingto reference this appendix Variable nameswere limited to eight characters Versionsof SPSSolderthan 12.0arelimitedto eight-character variablenames.The othervariablenamerulesstill apply.If you areusingan olderversionof SPSS,you needto makesureyou useeightor fewerlettersfor yourvariablenames The Data menu will look different The screenshotsin the text where the Data menu is shown will look slightly different if you are using an older version of SPSS.These missing or renamedcommandsdo not have any effect on this text, but the menusmay look slightly different If you are using a version of SPSS earlier than 10.0,the Analyzemenu will be called Statistics instead Dsta TlrBfqm rn4aa€ getu t oe&reoacs,., r hertYffd,e l|]lrffl Clsl*t GobCse",, Graphing functions Prior to SPSS12.0,the graphingfunctionsof SPSSwerevery limited.If you are using a version of SPSSolder than version 12.0, third-partysoftwarelike Excel or of graphs.If you areusingVersion14.0of for theconstruction SigmaPlotis recommended graphing to Chapter4, whichdiscusses thesoftware,useAppendixF asan alternative l 19 Appendix E Information for Usersof Earlier Versionsof SPSS Variableiconsindicatemeasurement type In versions of SPSS earlier than 14.0,variableswere represented in dialog boxes with their variable label and an icon that represented whether the variable was string or numeric (the examplehere shows all variablesthat were numeric) Starting with Version 14.0, SPSS shows additional information about each variable Icons now representnot only whether a variable is numeric or not, but also what type of measurementscale it is Nominal variables are representedby the & icon Ordinal variables are representedby the dfl i.on Interval and ratio variables(SPSSrefers to them as scale variables) are represented bv the d i"on f Mlcrpafr&nlm /srsinoPtrplecnft / itsscpawei [hura /v*tctaweir**&r /TimanAccAolao 1c I $ Cur*ryU Orlgin ClNrmlcnu clrnaaJ dq$oc.t l"ylo.:J It liqtq'ftc$/droyte sqFr*u.,| 4*r.-r-l qql{.,I SeveralSPSSdata filescan now be openat once Versionsof SPSSolder than 14.0 could have only one data file open at a time Copying data from one file to another entailed a tedious process of copying/opening files/pastingletc.Starting with version 14.0, multiple data files can be open at the same time When multiple files are open,you can selectthe one you want to work with using the Windowcommand md* Heb t|sr $$imlzeA[ Whdows lCas,sav [Dda*z] - S55 DctoEdtry t20 AppendixF GraphingDatawithSPSS13.0and14.0 This appendixshouldbe usedas an alternativeto Chapter4 whenyou are using SPSS13.0or 14.0.Theseproceduresmay alsobe usedin SPSS15.0,if desired,by selectingLegacyDialogsinsteadof ChortBuilder GraphingBasics In addition to the frequency distributions,the measuresof central tendency and measuresof dispersiondiscussedin Chapter3, graphing is a useful way to summarize,organize,and reduceyour data It has been said that a picture is worth a thousandwords In the caseof complicateddatasets,that is certainlytrue With SPSSVersion 13.0 and later,it is now possibleto make publication-quality graphsusing only SPSS.One importantadvantageof using SPSSinsteadof other software to createyour graphs(e.9., Excel or SigmaPlot)is that the data have alreadybeen entered Thus, duplicationis eliminated,and the chanceof making a transcriptionerror is reduced Editing SP,S,SGraphs Whatever command you use to create your graph, you will probably want to some editing to make it look exactly the way you want In SPSS,you this in much the sameway that you edit graphsin other software programs (e.9., Excel) In the output window, select your graph (thus creating handles around the outside of the entire object) and righrclick Then, click SPSSChart Object, then click Open Alternatively, you can double-click on the graph to open it for editing tl 9:.1tl 1bl rl l @l kl D l ol rl : j 8L l , l t21 AppendixF GraphingDatawith SPSS13.0and 14.0 Whenyou openthe graphfor editing,theChartEditor HSGlHffry;' window and the correspondingProperties window will appear I* -l ql ryl OnceChartEditoris open,you caneasilyedit eachelementof the graph.To select just click on therelevantspoton the graph.For example,to selectthe element an element, representing the title of the graph,click somewhere on the title (the word "Histogram"in theexamplebelow) Once you have selectedan element,you can tell that the correctelementis selected becauseit will havehandlesaroundit If the item you have selectedis a text element(e.g.,the title of the graph),a cursor will be presentand you can edit the text as you would in word processingprograms.If you would like to changeanotherattributeof the element(e.g., the color or font size), use the Propertiesbox (Text propertiesare shownabove) t22 AppendixF GraphingDatawith SPSS13.0and 14.0 With a little practice,you can makeexcellentgraphs usingSPSS.Onceyour graphis formattedthe way you want it, simplyselectFile,thenClose Data Set For the graphingexamples,we will usea new set of data.Enterthe databelowand savethe file as HEIGHT.sav The data representparticipants' HEIGHT (in inches), WEIGHT(in pounds), andSEX(l : male,2= female) HEIGHT 66 69 73 72 68 63 74 70 66 64 60 67 64 63 67 65 WEIGHT 150 155 160 160 150 140 165 150 110 100 52 ll0 105 100 ll0 105 SEX r I I I l l I I 2 2 2 Checkthat you haveenteredthe datacorrectlyby calculatinga mean for eachof the threevariables(click Analyze,thenDescriptiveStatistics,thenDescriptives).Compare yourresultswith thosein thetablebelow Descrlptlve Statlstlcs std Minimum Maximum N ntrt(,n I 'to OU.UU WEIGHT SEX 16 16 95.00 1.00 Valid N (listwise) 16 123 Deviation Mean I1.U U oo.YJ/0 J 9U O/ 165.00 129.0625 26.3451 2.00 5164 1.s000 AppendixF GraphingDatawith SPSS13.0and 14.0 Bar Charts,PieCharts,and Histograms Description Bar charts,pie charts,and histogramsrepresentthe number of times each scoreoccurs by varying the height of a bar or the size of a pie piece.They are graphicalrepresentations of the frequencydistributionsdiscussedin Chapter3 Drawing Conclusions The Frequenciescommandproducesoutput that indicatesboth the number of cases in the sample with a particular value and the percentageof caseswith that value Thus, conclusionsdrawn should relate only to describing the numbers or percentagesfor the sample.If the dataare at leastordinal in nature,conclusionsregardingthe cumulativepercentages and/orpercentilescan alsobe drawn SPSS Data Format You needonlv one variableto usethis command Running the Command The Frequenciescommand will produce I gnahao Qr4hs $$ities graphical frequency distributions.Click Analyze, Regorts then Descriptive Statistics,then Frequencies.You @ will be presentedwith the main dialog box for the : lauor Comps?U6ar1s Frequenciescommand, where you can enter the ' Eener.lllnEarlrlodsl variables for which you would like to create r'txedModds Qorrelate graphsor charts.(SeeChapter3 for other options availablewith this command.) tro ps8l 8"" I i BrsirbUvss,; Explorc.,, 9or*abr,., ) ) ; &dtlo Click the Chartsbuttonat the bottom to produce frequencydistributions Charts This will give you the Frequencies: dialogbox ."-41 E C hartTl p- " ' -* , c[iffi (e : q,l s r ur ' sachalts l* rfb chilk kj -i : ,i , ,,,, I , j r llrroclu* ,' There are three types of charts under this command: Bar charts, Pie charts, andHistograms.For each type, the f axis can be either a frequency count or a percentage(selectedthrough the Chart Valuesoption) You will receivethe chartsfor any variablesselectedin the main Frequenciescommanddialog box 124 I C " ,tt "5l u-,,,,:, l- :+;:'.n '1 i rChatVdues' , 15 Erecpencias l -, : f Porcer*ag$ : i - - ::- ,- AppendixF GraphingDatawith SPSS13.0and 14.0 Output The bar chart consistsof a Y axis, representing the frequency, and an X axis, representing each score Note that the only values representedon the X axis are those with nonzero frequencies(61, 62, and 7l are not represented) hrleht 1.5 c a f s a L 1.0 66.00 67.00 68.00 h.llht : ea t 61@ llil@ I 65@ os@ I r:@ o 4@ g i9@ o i0@ a i:@ B rro o :aa ifr The pie chart shows the percentageof the whole that is representedby eachvalue The Histogramcommandcreatesa groupedfrequencydistribution.The range of scores is split into evenly spaced groups.The midpoint of each group is plotted on the X axis, and the I axis represents the numberof scoresfor each group If you selectLl/ithNormal Curve,a normal curve will be superimposed over the distribution.This is very useful for helping you determineif the distribution you haveis approximately normal M.Sffi td 0.v 1.106?: ff.l$ h{ghl Practice Exercise Use PracticeData Set I in Appendix B After you have enteredthe data,constructa histogramthat representsthe mathematicsskills scoresand displaysa normal curve, and a bar chart that representsthe frequenciesfor the variableAGE t25 AppendixF GraphingDatawith SPSS13.0and 14.0 Scatterplots Description Scatterplots(also called scattergramsor scatterdiagrams)display two values for eachcasewith a mark on the graph.The Xaxis representsthe value for one variable.The / axis representsthe value for the secondvariable Assumptions Both variablesshouldbe interval or ratio scales.If nominal or ordinal data are used,be cautiousaboutyour interpretationof the scattergram .SP,t^tData Format You needtwo variablesto perform this command Running the Command I gr"pl,u Stllities Add-gns : You can produce scatterplotsby clicking Graphs, then I Scatter/Dot.This will give you the first Scatterplotdialog box i Selectthe desiredscatterplot(normally,you will select Simple ! Scatter),then click Define xl *t m m Simpla Scattal 0veday Scattel ffi ffi Mahix Scattel ffi sittpt" lelLl Oot li Definell - q"rylJ , Helo I 3,0 Scatter ffil;|rlil',r m s.fd ,- 9dMrk6by ,- L*dqs.bx | ,J l IJ T-P*lb 8off, rl[I ti : C*trK rI[I l*tCrtc 3*J qej *fl This will give you the main Scatterplot dialog box Enter one of your variablesas the I axis and the secondas the X axis For example, using the HEIGHT.sav data set, enter HEIGHT as the f axis and WEIGHT as the X axis Click oK - -' ' I'u;i** L":# 126 AppendixF GraphingDatawith SPSS13.0and 14.0 Output X andI levels Theoutputwill consistof a markfor eachsubjectat theappropriate 74.00 r20.m Adding a Third Variable Even though the scatterplotis a twodimensionalgraph,it canplot a third variable To makeit so,enterthethird variablein the SetMarkers by field.In our example,we will enterthe variable SEX in the ^SelMarkers by space Now our outputwill havetwo different sets of marks One set representsthe male participants, the and the secondset represents femaleparticipants Thesetwo setswill appear in differentcolorson your screen.You canuse the SPSSchart editor to make them different shapes, asin thegraphthatfollows t27 fa, I e- l at.l ccel x*l AppendixF GraphingDatawith SPSS13.0and 14.0 Graph sox aLm o 2.6 72.00 70.00 58.00 c I s 56.00 o 64.00 oo o 52.00 !00.00 120.m 110.@ r60.00 wrlght Practice Exercise UsePracticeDataSet2 in AppendixB Constructa scatterplot to examinethe relationshipbetweenSALARY andEDUCATION Advanced Bar Charts Description You canproducebar chartswith theFrequencies command(seeChapter4, Section 4.3) Sometimes, however,we are interested in a bar chartwherethe I axis is not a frequency.To producesucha chart,we needto usetheBar Chartscommand SPS,SData Format At leasttwo variablesare neededto performthis command.Thereare two basic kinds of bar charts-thosefor between-subjects designsand thosefor repeated-measures designs.Usethe between-subjects methodif onevariableis the independentvariableand the otheris the dependentvariable.Use the repeated-measures methodif you havea dependentvariable for eachvalueof the G"dr tJt$ths Mdsns €pkrv independentvariable(e.g.,you wouldhavethreevariablesfor a IrfCr$We designwith three valuesof the independentvariable) This ) Map normallyoccurswhenyou takemultipleobservations overtime 128 ]1 AppendixF GraphingDatawith SPSS13.0and 14.0 Running the Command Click Graphs,thenBar for eithertypeof bar chart This will openthe Bar Chartsdialog box If you haveone independentvariable, selectSimple.If you have more thanone,selectClustered design,select If you are usinga between-subjects Summariesfor groups of cases.If you are using a repeated-measures design, select Summariesof separate variables graph,you If you are creatinga repeatedmeasures will seethe dialog box below.Move eachvariableoverto theBars Representarea,and SPSSwill placeit insideparentheses followingMean.This will give you a graphlike the one below at right Note that this exampleusesthe dataenteredin Section6.4 (Chapter6) GRADES.sav lr# I t*ls o rhd Practice Exercise Use PracticeDataSet I in AppendixB Constructa bar graphexaminingthe relaskills scoresandmaritalstatus.Hint: In the BarsRepresent tionshipbetweenmathematics area.enterSKILL asthevariable t29 ... l.doFfihnt Vdi.bb I Notice SPSSis a registeredtrademarkof SPSS, Inc Screenimages@ by SPSS, Inc and MicrosoftCorporation.Usedwith permission This book is not approvedor sponsoredby SPSS "PyrczakPublishing"is... AppendixE Informationfor Usersof EarlierVersionsof SPSS l19 AppendixF GraphingDatawith SPSS1 3.0and 14.0 t2l tv ChapterI GettingStarted Section1.1 StartingSPSS ffi$ t't**** ffi c rrnoitllttt (- lhoari{irgqrory... Start, then clicking on Programs, then on SPSS On many installations,there will be an SPSSicon on the desktopthat you can double-click to start the program When SPSS is started,you may be presentedwith