Table 1. Repeated Measures ANOVA for Dwell Time (N = 138).
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index term SS MS N DF f Pr(>|f|)
1 cesd_group 0.000156 0.000156 1 135.999999 0.074957 0.7847
2 aoi 0.041991 0.041991 1 412.000001 20.155594 0.0
3 trialType 0.000944 0.000944 1 412.000001 0.453030 0.5013
index sigma logLik AIC BIC deviance df.residual
1 0.045643 730.979201 -1449.958402 -1424.077113 -1495.248944 546

Type III Analysis of Variance Table with Satterthwaite's method ['anova'].

Statistical Analysis

Participants with 'Dotloc' or 'Stimulus' Onset Error median above 3SD (n = 31, 18.7%) were excluded from analysis (see methods). We employed a repeated measures ANOVA using the anova() function in the stats R package (R Core Team, 2013; Chambers, Hastie, 1992). For our model, CESD Score ('Low' (<16) and 'High' (≥16)), Area of Interest (sad, neutral images), and Stimulus (IAPS, POFA). were included as main effects. Random effects for Participant. was included in the model to account for their respective variation in their slopes and intercepts. Dwell Time was used as the outcome measure.

For our analysis of Dwell Time, our results revealed no statistically significant effect of CESD Score (F (1, 135) = 0.075, p = 0.7847), a statistically significant effect of Area of Interest (F (1, 412) = 20.1556, p = 0.00E+00), no statistically significant effect of Stimulus (F (1, 412) = 0.453, p = 0.5013).

Table 2. Pairwise Comparisons of Estimated Marginal Means.
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index Contrasts estimate SE t Pr(>|t|)
1 High,neutral,iaps - Low,neutral,iaps -0.003953 0.014439 -0.273783 0.8636
2 High,neutral,iaps - High,sad,iaps -0.017444 0.003885 -4.489498 0.0001
3 High,neutral,iaps - Low,sad,iaps -0.021397 0.014952 -1.430982 0.3677
4 High,neutral,iaps - High,neutral,pofa -0.002615 0.003885 -0.673075 0.7785
5 High,neutral,iaps - Low,neutral,pofa -0.006568 0.014952 -0.439278 0.8046
6 High,neutral,iaps - High,sad,pofa -0.020059 0.005495 -3.650491 0.0018
7 High,neutral,iaps - Low,sad,pofa -0.024012 0.015449 -1.554265 0.3093
8 Low,neutral,iaps - High,sad,iaps -0.013490 0.014952 -0.902226 0.6605
9 Low,neutral,iaps - Low,sad,iaps -0.017444 0.003885 -4.489498 0.0001
10 Low,neutral,iaps - High,neutral,pofa 0.001338 0.014952 0.089478 0.9288
11 Low,neutral,iaps - Low,neutral,pofa -0.002615 0.003885 -0.673075 0.7785
12 Low,neutral,iaps - High,sad,pofa -0.016106 0.015449 -1.042504 0.5767
13 Low,neutral,iaps - Low,sad,pofa -0.020059 0.005495 -3.650491 0.0019
14 High,sad,iaps - Low,sad,iaps -0.003953 0.014439 -0.273783 0.8636
15 High,sad,iaps - High,neutral,pofa 0.014828 0.005495 2.698619 0.0309
16 High,sad,iaps - Low,neutral,pofa 0.010875 0.015449 0.703948 0.7785
17 High,sad,iaps - High,sad,pofa -0.002615 0.003885 -0.673075 0.7785
18 High,sad,iaps - Low,sad,pofa -0.006568 0.014952 -0.439278 0.8046
19 Low,sad,iaps - High,neutral,pofa 0.018782 0.015449 1.215709 0.4892
20 Low,sad,iaps - Low,neutral,pofa 0.014828 0.005495 2.698619 0.0309
21 Low,sad,iaps - High,sad,pofa 0.001338 0.014952 0.089478 0.9288
22 Low,sad,iaps - Low,sad,pofa -0.002615 0.003885 -0.673075 0.7785
23 High,neutral,pofa - Low,neutral,pofa -0.003953 0.014439 -0.273783 0.8636
24 High,neutral,pofa - High,sad,pofa -0.017444 0.003885 -4.489498 0.0001
25 High,neutral,pofa - Low,sad,pofa -0.021397 0.014952 -1.430982 0.3676
26 Low,neutral,pofa - High,sad,pofa -0.013490 0.014952 -0.902226 0.6605
27 Low,neutral,pofa - Low,sad,pofa -0.017444 0.003885 -4.489498 0.0001
28 High,sad,pofa - Low,sad,pofa -0.003953 0.014439 -0.273783 0.8636
The 'Estimated Marginal Means' table provides a list pairwise comparisons for each level and factor in our model (emmeans package, Version 1.3.2).
Figure 1. Pairwise Comparisons Plot.
Last Updated: 2019-04-07 13:42:12
This boxplot provides a comparison of [cesd_group] and across both IAPS and POFA stimuli. Both IAPS and POFA plots were nornalized to allow direct comparison.
Figure 2. Pairwise Comparisons Plot.
Last Updated: 2019-04-07 13:42:12
This boxplot provides a comparison of [aoi] and across both IAPS and POFA stimuli. Both IAPS and POFA plots were nornalized to allow direct comparison.
Figure 3. Q-Q Plot (iaps, pofa).
Last Updated: 2019-04-07 13:42:12
The Normal Q-Q plot compares the standardized residuals against the theoretical quantiles from a standard normal distribution. If the model residuals are normally distributed, then the points on this graph will be plotted in a generally straight line.
Figure 4. Residuals vs Fitted Plot (iaps, pofa).
Last Updated: 2019-04-07 13:42:12
The Residuals vs Fitted plot is used to identify residual distribution. If residuals are following a visible trend on the graph, then the homogeneity assumption was violated.