Results

ANCOVA

ANCOVA - 1 year later
	Sum of Squares	df	Mean Square	F	p
Baseline	124.006	1	124.0057	1313.16	< .001
Blue/Red	0.108	1	0.1077	1.14	0.287
Residuals	15.865	168	0.0944

[3]

Assumption Checks

Homogeneity of Variances Tests
	Statistic	df	df2	p
Levene's	12.9	1	169	< .001
Bartlett's	6.98	1		0.008
Note. Additional results provided by moretests

Normality tests
	statistic	p
Shapiro-Wilk	0.948	< .001
Kolmogorov-Smirnov	0.0976	0.077
Anderson-Darling	2.05	< .001
Note. Additional results provided by moretests

Descriptives

Descriptives
	Blue/Red	Change
N	Blue	81
	Red	90
Missing	Blue	4
	Red	2
Mean	Blue	0.142
	Red	0.0878
Median	Blue	0.150
	Red	0.0900
Standard deviation	Blue	0.382
	Red	0.219
Minimum	Blue	-1.17
	Red	-0.530
Maximum	Blue	1.57
	Red	0.750

Plots

Change

Independent Samples T-Test

Independent Samples T-Test
		Statistic		df	p
Change	Student's t	1.16	ᵃ	169	0.248
	Welch's t	1.13		124	0.261
	Mann-Whitney U	3128			0.110
Note. Hₐ μ _Blue ≠ μ _Red
ᵃ Levene's test is significant (p < .05), suggesting a violation of the assumption of equal variances

Descriptives

Descriptives
	Blue/Red	Baseline	1 year later
N	Blue	85	81
	Red	91	90
Missing	Blue	0	4
	Red	1	2
Mean	Blue	2.96	2.79
	Red	2.75	2.69
Median	Blue	2.78	2.67
	Red	2.79	2.71
Standard deviation	Blue	1.00	1.04
	Red	0.766	0.777
Minimum	Blue	1.10	0.780
	Red	0.860	0.940
Maximum	Blue	5.65	5.85
	Red	4.70	4.14

Plots

Baseline

1 year later

Repeated Measures ANOVA

Within Subjects Effects
	Sum of Squares	df	Mean Square	F	p
BaseVsLater	1.1288	1	1.1288	23.92	< .001
BaseVsLater ✻ Blue/Red	0.0635	1	0.0635	1.35	0.248
Residual	7.9746	169	0.0472
Note. Type 3 Sums of Squares

[4]

Between Subjects Effects
	Sum of Squares	df	Mean Square	F	p
Blue/Red	1.52	1	1.52	0.981	0.323
Residual	262.46	169	1.55
Note. Type 3 Sums of Squares

Assumptions

Tests of Sphericity
	Mauchly's W	p		Greenhouse-Geisser ε	Huynh-Feldt ε
BaseVsLater	1.00	NaN	ᵃ	1.00	1.00
ᵃ The repeated measures has only two levels. The assumption of sphericity is always met when the repeated measures has only two levels

Homogeneity of Variances Test (Levene's)
	F	df1	df2	p
Baseline	7.57	1	169	0.007
1 year later	4.44	1	169	0.037

Q-Q Plot

Independent Samples T-Test

Independent Samples T-Test
		Statistic		df	p
DiffBetwSqRoots	Student's t	1.16	ᵃ	169	0.248
Note. Hₐ μ _Blue ≠ μ _Red
ᵃ Levene's test is significant (p < .05), suggesting a violation of the assumption of equal variances

Assumptions

Normality Test (Shapiro-Wilk)
	W	p
DiffBetwSqRoots	0.947	< .001
Note. A low p-value suggests a violation of the assumption of normality

Homogeneity of Variances Test (Levene's)
	F	df	df2	p
DiffBetwSqRoots	14.1	1	169	< .001
Note. A low p-value suggests a violation of the assumption of equal variances

[3]

Repeated Measures ANOVA

Within Subjects Effects
	Sum of Squares	df	Mean Square	F	p
Sq	205.83582	1	205.83582	2724.9926	< .001
Sq ✻ Blue/Red	0.00551	1	0.00551	0.0729	0.787
Residual	12.76563	169	0.07554
Note. Type 3 Sums of Squares

[4]

Between Subjects Effects
	Sum of Squares	df	Mean Square	F	p
Blue/Red	0.185	1	0.1846	2.12	0.148
Residual	14.738	169	0.0872
Note. Type 3 Sums of Squares

Assumptions

Homogeneity of Variances Test (Levene's)
	F	df1	df2	p
SqRtBase	5.12	1	169	0.025
DiffBetwSqRoots	14.13	1	169	< .001

Q-Q Plot

References

[1] The jamovi project (2022). jamovi. (Version 2.3) [Computer Software]. Retrieved from https://www.jamovi.org.

[2] R Core Team (2021). R: A Language and environment for statistical computing. (Version 4.1) [Computer software]. Retrieved from https://cran.r-project.org. (R packages retrieved from MRAN snapshot 2022-01-01).

[3] Fox, J., & Weisberg, S. (2020). car: Companion to Applied Regression. [R package]. Retrieved from https://cran.r-project.org/package=car.

[4] Singmann, H. (2018). afex: Analysis of Factorial Experiments. [R package]. Retrieved from https://cran.r-project.org/package=afex.