LMM Instruction
Read Dataset
fullData <- read_csv("C:/R/exp_1/results/eeg/fullData.csv")
Behavioural Data
# lmer(rtDet ~ 1 + group + trialType + cuePos + (1|id), data = data)
Select Comparisons
# Change for every comparisons
data <- fullData |>
filter(cuePos == "Left",
hemis == "right",
ROI == "Occ")
EEG Data
#QQ
#Residual QQ plot
qq_p <- lm(alpha ~ group*trialType, data = data)
ggqqplot(residuals(qq_p))

Normality Testing
normality <- data |>
group_by(group, trialType) |>
shapiro_test(alpha) #must be P >.05
normality
## # A tibble: 6 × 5
## group trialType variable statistic p
## <chr> <chr> <chr> <dbl> <dbl>
## 1 C G alpha 0.950 0.569
## 2 C NG alpha 0.781 0.0709
## 3 MA G alpha 0.988 0.794
## 4 MA NG alpha 0.881 0.328
## 5 MO G alpha 0.831 0.191
## 6 MO NG alpha 0.997 0.893
LMM
# Do this for each ROI(4) in each cuePos(2, with or without neutral subtraction??)
lmm <- lmer(alpha ~ group * trialType * (1|id), data = data)
summary(lmm)
## Linear mixed model fit by REML ['lmerMod']
## Formula: alpha ~ group * trialType * (1 | id)
## Data: data
##
## REML criterion at convergence: 40.4
##
## Scaled residuals:
## Min 1Q Median 3Q Max
## -1.73255 -0.32851 0.01463 0.43882 1.62406
##
## Random effects:
## Groups Name Variance Std.Dev.
## id (Intercept) 0.0000 0.0000
## Residual 0.9833 0.9916
## Number of obs: 18, groups: id, 9
##
## Fixed effects:
## Estimate Std. Error t value
## (Intercept) -0.3263 0.5725 -0.570
## groupMA -0.4926 0.8097 -0.608
## groupMO -2.3297 0.8097 -2.877
## trialTypeNG -0.3503 0.8097 -0.433
## groupMA:trialTypeNG 0.4135 1.1450 0.361
## groupMO:trialTypeNG 0.3371 1.1450 0.294
##
## Correlation of Fixed Effects:
## (Intr) gropMA gropMO trlTNG gMA:TN
## groupMA -0.707
## groupMO -0.707 0.500
## trialTypeNG -0.707 0.500 0.500
## grpMA:trTNG 0.500 -0.707 -0.354 -0.707
## grpMO:trTNG 0.500 -0.354 -0.707 -0.707 0.500
## optimizer (nloptwrap) convergence code: 0 (OK)
## boundary (singular) fit: see help('isSingular')
ANOVA Base
anova <- aov(alpha ~ group * trialType, data = data)
summary(anova)
## Df Sum Sq Mean Sq F value Pr(>F)
## group 2 16.539 8.269 8.410 0.00521 **
## trialType 1 0.045 0.045 0.046 0.83397
## group:trialType 2 0.145 0.073 0.074 0.92923
## Residuals 12 11.800 0.983
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
ANOVA rstatix
anova_rstatix <- anova_test(data = data,
formula = alpha ~ group * trialType,
dv = alpha,
wid = id,
between = c(group, trialType),
effect.size = "pes") #"Effect Size (ƞ2p)"
anova_rstatix
## ANOVA Table (type II tests)
##
## Effect DFn DFd F p p<.05 pes
## 1 group 2 12 8.410 0.005 * 0.584
## 2 trialType 1 12 0.046 0.834 0.004
## 3 group:trialType 2 12 0.074 0.929 0.012
# anova_rstatix |>
# kbl() |>
# kable_minimal()
#Cohen's D Benchmarks
#.01: Small effect size
#.06: Medium effect size
#.14 or higher: Large effect size