1. TAUCHI – Tampere Unit for Computer-Human Interaction Experimental Research in IT Analysis – practical part Hanna Venesvirta

2. TAUCHI – Tampere Unit for Computer-Human Interaction Experimental task: select an object as fast as possible. Depend variable: selection time. One independent variable (diameter of an object) with three levels (diameter: 25, 30, and 40 mm). All the participants made the same task: within subject design.  one-way within subject ANOVA. Example analysis etc.

3. TAUCHI – Tampere Unit for Computer-Human Interaction Difference in the means! Is it significant?

4. TAUCHI – Tampere Unit for Computer-Human Interaction What is needed for a graph?

5. TAUCHI – Tampere Unit for Computer-Human Interaction Error bars to a graph? (Applies to MS Office 2007 & 2010) - Make the graph - Select the data series from the graph -> ”chart tools” is available - Select ”layout” – ”error bars” – ”more error bars options” - Here we use only ”positive” error bars – select ”plus” - ”Error amount” == ”custom” – select ”specify value” – select from the sheet the values you have calculated for the deviation (e.g., S.E.M.s) for ”positive error value” (MS Office 2013? E.g. http://www.officetooltips.com/excel/tips/adding_error_bars.html )

6. TAUCHI – Tampere Unit for Computer-Human Interaction Data to SPSS? Three ways (at least): 1) Input by hand Might be painful and cause errors 2) Copy-and-paste (from, e.g., Excel) Paste variable names to ”variable view” and data to ”data view” Note: SPSS is picky with variable names – avoid at least spaces and umlauts

7. TAUCHI – Tampere Unit for Computer-Human Interaction Data to SPSS? 3) Open data from, e.g., Excel Open – data – browse to data location – select the file type you are using Note: for the SPSS analysis you use only the data matrix (so no means or deviations etc. are used here)

8. TAUCHI – Tampere Unit for Computer-Human Interaction Parametric tests

9. TAUCHI – Tampere Unit for Computer-Human Interaction

12. Tests of Within-Subjects Effects Measure: MEASURE_1 SourceType III Sum of Squares dfMean SquareFSig. size Sphericity Assumed 4656395,95522328197,9775,567,008 Greenhouse-Geisser 4656395,9551,1803946581,0215,567,023 Huynh-Feldt 4656395,9551,2123842071,2655,567,022 Lower-bound 4656395,9551,0004656395,9555,567,029 Error(size) Sphericity Assumed 15892110,38138418213,431 Greenhouse-Geisser 15892110,38122,417708923,041 Huynh-Feldt 15892110,38123,027690149,988 Lower-bound 15892110,38119,000836426,862 From the output, find table ”tests of within-subjects effects”

13. TAUCHI – Tampere Unit for Computer-Human Interaction - So there is a difference, but where? -> pairwise comparisons Comparing 25 mm to 30 mm, 25 mm to 40 mm, and 30 mm to 40 mm -> 3 comparisons Two ways: 1) via the GLM menu (showed first) - calculates automatically the Bonferroni correction but does not tell the t-values 2) via pairwise t-tests-menu (2nd) - gives t-values - remember to calculate the B-correction by hand (α/no. of comparisons)

14. TAUCHI – Tampere Unit for Computer-Human Interaction

18. Estimates Measure: MEASURE_1 sizeMeanStd. Error95% Confidence Interval Lower BoundUpper Bound 1 1890,233276,2521312,0312468,435 2 1355,983105,3041135,5801576,386 3 1255,46495,3891055,8121455,116 Pairwise Comparisons Measure: MEASURE_1 (I) size(J) size Mean Difference (I-J) Std. ErrorSig. b 95% Confidence Interval for Difference b Lower BoundUpper Bound 1 2 534,250265,783,177-163,4591231,960 3 634,769 * 210,735,02181,5681187,971 2 1 -534,250265,783,177-1231,960163,459 3 100,519102,0491,000-167,371368,408 3 1 -634,769 * 210,735,021-1187,971-81,568 2 -100,519102,0491,000-368,408167,371 Based on estimated marginal means *. The mean difference is significant at the,05 level. b. Adjustment for multiple comparisons: Bonferroni. size From the output, find ”pairwise comparisons” under ”estimated mariginal means”: 1=25 mm 2=30 mm 3=40 mm Check in which order your columns were and you will find out where the difference is.

19. TAUCHI – Tampere Unit for Computer-Human Interaction

21. Paired Samples Test Paired DifferencestdfSig. (2-tailed) MeanStd. DeviationStd. Error Mean 95% Confidence Interval of the Difference LowerUpper Pair 1 Diameter25mm - Diameter30mm 534,25047932330 8200 1188,6194789491 00000 265,78339543105 6930 - 22,040560576190 714 1090,5415192228 07000 2,01019,059 Pair 2 Diameter25mm - Diameter40mm 634,76911027568 9700 942,43528288740 0500 210,73493569304 7280 193,69582076596 8620 1075,8423997854 10600 3,01219,007 Pair 3 Diameter30mm - Diameter40mm 100,51863095238 1600 456,37710097444 7500 102,04902211531 5080 - 113,07242706381 1220 314,10968896857 4230,98519,337 From the output, find ”paired samples test”

22. TAUCHI – Tampere Unit for Computer-Human Interaction Tests of Within-Subjects Effects Measure: MEASURE_1 SourceType III Sum of Squares dfMean SquareFSig. size Sphericity Assumed 4656395,95522328197,9775,567,008 Greenhouse-Geisser 4656395,9551,1803946581,0215,567,023 Huynh-Feldt 4656395,9551,2123842071,2655,567,022 Lower-bound 4656395,9551,0004656395,9555,567,029 Error(size) Sphericity Assumed 15892110,38138418213,431 Greenhouse-Geisser 15892110,38122,417708923,041 Huynh-Feldt 15892110,38123,027690149,988 Lower-bound 15892110,38119,000836426,862 Reporting parametric ANOVA

23. TAUCHI – Tampere Unit for Computer-Human Interaction Pairwise Comparisons Measure: MEASURE_1 (I) size(J) size Mean Difference (I-J) Std. ErrorSig. b 95% Confidence Interval for Difference b Lower BoundUpper Bound 1 2 534,250265,783,177-163,4591231,960 3 634,769 * 210,735,02181,5681187,971 2 1 -534,250265,783,177-1231,960163,459 3 100,519102,0491,000-167,371368,408 3 1 -634,769 * 210,735,021-1187,971-81,568 2 -100,519102,0491,000-368,408167,371 Based on estimated marginal means *. The mean difference is significant at the,05 level. b. Adjustment for multiple comparisons: Bonferroni. Estimates Measure: MEASURE_1 sizeMeanStd. Error95% Confidence Interval Lower BoundUpper Bound 1 1890,233276,2521312,0312468,435 2 1355,983105,3041135,5801576,386 31255,46495,3891055,8121455,116 Reporting pairwise comparisons (1) ”MD” stands for ”Mean Difference” 1=25 mm 2=30 mm 3=40 mm Check in which order your columns were and you will find out where the difference is.

24. TAUCHI – Tampere Unit for Computer-Human Interaction Paired Samples Test Paired DifferencestdfSig. (2-tailed) MeanStd. DeviationStd. Error Mean 95% Confidence Interval of the Difference LowerUpper Pair 1 Diameter25mm - Diameter30mm 534,25047932330 8200 1188,6194789491 00000 265,78339543105 6930 - 22,040560576190 714 1090,5415192228 07000 2,01019,059 Pair 2 Diameter25mm - Diameter40mm 634,76911027568 9700 942,43528288740 0500 210,73493569304 7280 193,69582076596 8620 1075,8423997854 10600 3,01219,007 Pair 3 Diameter30mm - Diameter40mm 100,51863095238 1600 456,37710097444 7500 102,04902211531 5080 - 113,07242706381 1220 314,10968896857 4230,98519,337 Reporting pairwise comparisons (2)

25. TAUCHI – Tampere Unit for Computer-Human Interaction Non-parametric one way within subjects analysis of variance: Friedman test

26. TAUCHI – Tampere Unit for Computer-Human Interaction

28. NPar Tests Descriptive Statistics NMeanStd. DeviationMinimumMaximum Diameter25mm 201890,23341235,436131006,576462,00 Diameter30mm 201355,9829470,93297738,252521,43 Diameter40mm 201255,4643426,59355747,252603,00 Friedman Test Ranks Mean Rank Diameter25mm 2,60 Diameter30mm 1,75 Diameter40mm1,65 Test Statistics a N 20 Chi-Square 10,900 df 2 Asymp. Sig.,004 a. Friedman Test From the output, find ”test statistics”

29. TAUCHI – Tampere Unit for Computer-Human Interaction Post hocs for Friedman: Wilcoxon (Repeated Measures) Signed-Rank test

30. TAUCHI – Tampere Unit for Computer-Human Interaction

32. Wilcoxon Signed Ranks Test Ranks NMean RankSum of Ranks Diameter30mm - Diameter25mm Negative Ranks 14 a 11,64163,00 Positive Ranks 6b6b 7,8347,00 Ties 0c0c Total 20 Diameter40mm - Diameter25mm Negative Ranks 18 d 11,00198,00 Positive Ranks 2e2e 6,0012,00 Ties 0f0f Total 20 Diameter40mm - Diameter30mm Negative Ranks 9g9g 12,44112,00 Positive Ranks 11 h 8,9198,00 Ties 0i0i Total 20 a. Diameter30mm < Diameter25mm b. Diameter30mm > Diameter25mm c. Diameter30mm = Diameter25mm d. Diameter40mm < Diameter25mm e. Diameter40mm > Diameter25mm f. Diameter40mm = Diameter25mm g. Diameter40mm < Diameter30mm h. Diameter40mm > Diameter30mm i. Diameter40mm = Diameter30mm Test Statistics a Diameter30mm - Diameter25mm Diameter40mm - Diameter25mm Diameter40mm - Diameter30mm Z -2,165 b -3,472 b -,261 b Asymp. Sig. (2-tailed),030,001,794 a. Wilcoxon Signed Ranks Test b. Based on positive ranks. From the output, find ”test statistics”

33. TAUCHI – Tampere Unit for Computer-Human Interaction Test Statistics a N 20 Chi-Square 10,900 df 2 Asymp. Sig.,004 a. Friedman Test Reporting Friedman’s test

34. TAUCHI – Tampere Unit for Computer-Human Interaction Reporting Wilcoxon test Test Statistics a Diameter30mm - Diameter25mm Diameter40mm - Diameter25mm Diameter40mm - Diameter30mm Z -2,165 b -3,472 b -,261 b Asymp. Sig. (2-tailed),030,001,794 a. Wilcoxon Signed Ranks Test b. Based on positive ranks. Note: doubleclick the table (twice) and you will see more accurate p-value (on this case p = 0.000517 so it is significant in 0.01 level as 0.01/3=0.0033..).