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SPSS WORKSHOP Please Log onto Your Computer Station User Name: type in your user ID Password: type in your password Domain: ASUAD If you have trouble signing in: – Then try signing in with westguest account User Name: westguest Password: asuwest Domain: (this computer) –Sometime after today’s class, please go to Technopolis (basement of library) to get your user ID fixed. Brief Introduction to Statistics with SPSS Roger Berger Mathematical Sciences & Applied Computing Department Rico Rivera Josh Fox Heather Ohton Tommy Aguila Christopher Zambakari Statistics Laboratory http://www.west.asu.edu/StatLab Workshop Overview • Workshop Objectives (p 1) – Overview of Basic Organization of SPSS – How to input raw data – How raw data file is edited in “variable view” – Perform basic data analyses • Table of Contents (p 2) Open up your internet Explorer http://www.west.asu.edu/StatLab • Click on Workshops • Click on Data Used for SPSS Workshops • Click on Res_Stat_Edited_Data.sav • Please save it in your Desktop. • Please do not open the data file • Close the internet brower. Open up your internet Explorer Click on My Network Places • Click on \\westfile\web\CGIWEB\statlab • Click on WorkshopExample.sav (SPSS file) • Click on WorkshopExample.xls (Excel file) • Please copy it to your Desktop. • Please do not open the data file SPSS Accessibility (p. 3) • Network access – Technopolis (basement of library) • Desktop (hard drive) installed – Computer Classrooms – Stat Lab Accessing the Statistic Laboratory (p. 3) • Location: CLCC 107 • Phone: (602) 543-6117 • Website: http://www.west.asu.edu/StatLab • Operating hours: See website (changes on a weekly basis) • When using the lab, please sign in at the front counter Support for Statistics (p. 4) • Function of Stat Lab – The Stat Lab staff assists students with aspects of statistical software. – The Stat Lab is not set up to provide one-on-one tutorial service for students on a regular basis. – However, we have and frequently do answer general statistic questions. • Statistics Tutoring (bottom of p 4) – Learning Enhancement Center – TRiO (SSS) program Procedures for Data Analysis (p. 6) Data Statistics Software Output Interpretation 1. Collect & organize data 2. Input & edit the data 3. Analyze data or create graphs 4. State results and interpret Please fill out the Research & Statistics Attitude Survey (Remove the last page of your handout) • Response – Strongly Disagree = 1 – Disagree = 2 – Agree = 3 – Strongly Agree = 4 • Sex – Male = 1 – Female = 2 • Age – Under 25 = 1 – 25 – 40 = 2 – Over 40 = 3 • Having ID column will help you keep track of cases • What do the first 5 questions (items) measure? • What do items 6 through 10 measure? Let’s Launch SPSS • Menu Bar – Data & Transform are used to manipulate the data in data editor (i.e., spread sheet) – Analyze and Graphs are used to create output • Tabs (bottom left hand corner of data editor, p. 7) – Data View • Columns: Variables (e.g., questions on survey) • Rows: Cases (e.g., survey) – Variable View • How we edit the variables • Give variables their names, labels, etc • Enter you survey into Data View Editing the Raw Data • Variable View – Tab (located lower left hand corner) – Pages 9 – 10 of your handout Retrieving an Edited Data • Save the data set to your desktop. • Call it “edited data” & your initials – E.g., editeddataRR • Now we are going to open up a new data set. • File > open > Data – Navigate to your desktop – Open up the data file that you downloaded from our website. Review of Workshop • We inputted raw data (from the survey) into the data editor • We edited a raw data file in “variable view” – pp. 9 - 10 • We retrieved an edited file and perform some basic statistical analyses. Two Topics • Prepping an Excel spreadsheet to be imported into SPSS • Types of Analyses of variance (ANOVA). Excel spreadsheet • Each column is indicative of a variable • First row contains the variable names • You want to keep the same rules that apply to variable names in SPSS • The subsequent rows contain the data for each case (subject) • Gender has two levels – Male = 1 – Female = 2 • Age has three levels – < 25 = 1 – 25 - 40 = 2 – > 40 = 3 • Time has three levels – Baseline = time0 – Time 1 = time1 – Time 2 = time2 • Composite scores for “attitude towards research” Excel spreadsheet I sorted the data based on gender and age variables for instructional purposes. Between subjects (aka independent samples) • What are two between-subject factors that have independent samples? – Gender: 2 samples – Age: 3 samples Within subjects (aka related samples) • What is the one within-subject factor that is indicative of three related samples? – Time: 3 samples Importing Excel Data into SPSS Stat Lab Staff: you may want to print this slide and follow the SPSS directions below • After formatting the data in Excel – First row contains the variable names – Other rows contain the data values • Save and close Excel file • Open up SPSS – Click on File > Open > Data – Navigate to the location you save the Excel file – In “Files of type:” choose either • Excel (*.xls) • or All files (*.*) • Open the Excel file you saved – You’ll get a dialogue box called: Opening Excel Data Source • There is a green check mark in box: Read variable names from the list from the first row of data • Worksheet: choose the worksheet in which the data is located • Click the OK button. – You just imported an excel file into SPSS Analysis of Variance • One-way ANOVA – One between subjects factor – Example: Age • Two-way ANOVA – Usually consist of two between subjects factors – Example: Age and Gender • Repeated Measures – One-way within subjects ANOVA • One within subjects factor • Example: Time – Two-way between and within subjects ANOVA • One between subjects factor (e.g., Time) • And one within subject factor (e.g., Age) One-way ANOVA You may want to open the SPSS data file that you downloaded. • Differences among 2 or more independent sample means with SPSS • Analysis of Variance • Analyze > Compare Means > One-Way ANOVA … • One dependent variable (e.g., baseline, time0) goes into the “Dependent List:” • One between subjects factor (e.g., Age) goes into “Factor:” • If the factor has more than three level, click on Post Hoc… – Click on Tukey and Dunett’s C (unless your instructor wants you to use a different one). – Click on continue • Click on Options – Chose • descriptive Statistics • Homogeneity of variance test • Perhaps on Means plot – Click on continue • Click on OK Descriptive Statistics Des criptives time0 95% Conf idence Interval f or Mean N Mean Std. Deviation Std. Error Low er Bound Upper Bound Minimum Max imum Under 25 33 14.12 3.267 .569 12.96 15.28 7 20 25 - 40 37 13.24 3.840 .631 11.96 14.52 7 20 Over 40 25 9.76 3.018 .604 8.51 11.01 6 18 Total 95 12.63 3.837 .394 11.85 13.41 6 20 • The first columns contains the three levels of the Age factor. • The mean column contains the mean “attitude toward statistics” •Does it appear that there may be an age effect? •Do you notice a trend? •Which age group has the greatest mean? F-test ANOVA time0 Sum of Squares df Mean Square F Sig. Betw een Groups 293.219 2 146.610 12.364 .000 Within Groups 1090.886 92 11.857 Total 1384.105 94 • The F-test looks tells us if there is an age effect. • Is the F-test significant? – Look at the p value (in column called Sig.) – Is it less than an alpha of .05? • However, the F-test does not tell us which pair of means are significantly different. • We look at the multiple comparisons for that. Multiple Comparisons Multiple Com parisons Dependent V ariable: time0 Mean Dif f erence 95% Conf idence Interval (I) age (J) age (I-J) Std. Error Sig. Low er Bound Upper Bound Tukey HSD Under 25 25 - 40 .878 .824 .538 -1.09 2.84 Over 40 4.361* .913 .000 2.19 6.54 25 - 40 Under 25 -.878 .824 .538 -2.84 1.09 Over 40 3.483* .891 .001 1.36 5.61 Over 40 Under 25 -4.361* .913 .000 -6.54 -2.19 25 - 40 -3.483* .891 .001 -5.61 -1.36 Dunnett C Under 25 25 - 40 .878 .850 -1.20 2.96 Over 40 4.361* .829 2.31 6.42 25 - 40 Under 25 -.878 .850 -2.96 1.20 Over 40 3.483* .873 1.33 5.64 Over 40 Under 25 -4.361* .829 -6.42 -2.31 25 - 40 -3.483* .873 -5.64 -1.33 *. The mean dif f erenc e is s ignif icant at the .05 lev el. •Mean difference column was calculated by subtracting the means for age categories in column (j) from means for age categories in column (I). •If there is an asterisk, the mean difference is significant. Two-way ANOVA • Analyze > General Linear Model > Univariate… • Dialogue box titled Univariate – Dependent variable: move one dependent variable (e.g., baseline: time0) – Fixed Factor(s): move in the between subjects factors (e.g., Gender and Age). Dialogue box titled Univariate (continued) • Click on Plots – Move one of factors into horizontal axis and the other into separate lines – Click Add – If you wish, you can do the inverse of that, then click add again – Click Continue Dialogue box titled Univariate (continued) • Click on Post Hoc… – Choose only factors that have three or more levels. (e.g., Age). – Click on Tukey and Dunett’s C (unless your instructor wants you to use different ones). – Click on continue Dialogue box titled Univariate (continued) • Click on Option… – Choose Descriptive statistics – Homogeneity tests – Click on continue • Click on OK Repeated Measures • Analyze > General Linear Model > Repeated Measures… • Dialogue box: Repeated Measures Define Factor(s) • Within-Subject Factor Name: – Change name to: time – Number of levels: 3 levels (i.e., baseline, time0, and time1) – Click on Add – Click on Define Dialogue Box: Repeated Measures • Within-Subjects Variables (time): – Choose the three variables (time0, time1, time2) the insert them in the correct order. – Between-Subjects Factor(s): • Insert the factors that you are interested in. • In this case, enter in Age. Dialogue Box: Repeated Measures (continued) • Click on Plots – I recommend that you move the Time factor into horizontal axis and the other (Age) into separate lines – Click Add – Click Continue Dialogue Box: Repeated Measures (continued) • Click on Post Hoc… – Choose only factor(s) that have three or more levels. (e.g., Age). – Click on Tukey and Dunett’s C (unless your instructor wants you to use different ones). – Click on continue Dialogue Box: Repeated Measures (continued) • Click on Option… – Choose Descriptive statistics – Homogeneity tests – Click on continue • Click on OK Stat Lab Resources • 12 PC computers, printer (free printing), and copier (limited use) • Office supplies (stapler, 3-hole puncher, paper clips) • Reference library (books can not leave the Stat Lab): – Introductory text books on Statistics & Research Methods – Publication manual of the American Psychological Association – Presenting your findings: a practical guide for creating tables – Displaying your findings: a practical guide for creating figures, posters, and presentations – Using SPSS for Windows & Macintosh: analyzing & understanding data analyses (helpful in interpreting the results and writing it in APA format) Thanks for having us as your guests We have to justify the Stat Lab conducting SPSS workshops. Could you please fill out the “SPSS workshop Evaluation” at last page of the packet. If would please write comments about • what you like most of the workshop, • what you have learned about the workshop, • how we may be able to improve it. We will greatly appreciate it. Thank You, Thanks for having us as your guests Do keep the “Research and Statistics Attitude Survey” you filled out. Please turn in the “SPSS Workshop Evaluation.” You can drop off this evaluation near the door. Please come and visit the Stat Lab (CLCC 107) Have a good day.
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