Az lme4 csomag szintaxisa
Az lme4 csomag az R hagyományos formula-jat egészíti ki azzal, hogy a
random hatásokat ()-ben kell megadnunk, | jellel elválasztva a random
hatás struktúráját magától a random faktortól.
- konstans + random konstans:
library(lme4)
## Loading required package: Matrix
mod0 <- lmer(scRT ~ 1 + (1 | Subject), data = lexdec_corr)
summary(mod0)
## Linear mixed model fit by REML ['lmerMod']
## Formula: scRT ~ 1 + (1 | Subject)
## Data: lexdec_corr
##
## REML criterion at convergence: 3947.4
##
## Scaled residuals:
## Min 1Q Median 3Q Max
## -2.5443 -0.6751 -0.0900 0.5266 5.6587
##
## Random effects:
## Groups Name Variance Std.Dev.
## Subject (Intercept) 0.3635 0.6029
## Residual 0.6625 0.8140
## Number of obs: 1594, groups: Subject, 21
##
## Fixed effects:
## Estimate Std. Error t value
## (Intercept) 0.002605 0.133131 0.02
- "valódi" fix hatás + random konstans + random slope:
mod_trial <- lmer(scRT ~ scTrial + (1 + scTrial | Subject),
data = lexdec_corr)
summary(mod_trial)
## Linear mixed model fit by REML ['lmerMod']
## Formula: scRT ~ scTrial + (1 + scTrial | Subject)
## Data: lexdec_corr
##
## REML criterion at convergence: 3932.5
##
## Scaled residuals:
## Min 1Q Median 3Q Max
## -2.6980 -0.6648 -0.0766 0.5195 5.7253
##
## Random effects:
## Groups Name Variance Std.Dev. Corr
## Subject (Intercept) 0.36429 0.6036
## scTrial 0.01695 0.1302 -0.33
## Residual 0.64584 0.8036
## Number of obs: 1594, groups: Subject, 21
##
## Fixed effects:
## Estimate Std. Error t value
## (Intercept) 0.002846 0.133246 0.021
## scTrial -0.034086 0.034885 -0.977
##
## Correlation of Fixed Effects:
## (Intr)
## scTrial -0.267
- keresztezett random hatások:
mod_crossed <- lmer(scRT ~ scTrial + (1 + scTrial | Subject) + (1 | Word),
data = lexdec_corr)
summary(mod_crossed)
## Linear mixed model fit by REML ['lmerMod']
## Formula: scRT ~ scTrial + (1 + scTrial | Subject) + (1 | Word)
## Data: lexdec_corr
##
## REML criterion at convergence: 3599.9
##
## Scaled residuals:
## Min 1Q Median 3Q Max
## -2.3768 -0.6269 -0.1168 0.4464 6.0555
##
## Random effects:
## Groups Name Variance Std.Dev. Corr
## Word (Intercept) 0.18275 0.4275
## Subject (Intercept) 0.37168 0.6097
## scTrial 0.01655 0.1286 -0.29
## Residual 0.46785 0.6840
## Number of obs: 1594, groups: Word, 79; Subject, 21
##
## Fixed effects:
## Estimate Std. Error t value
## (Intercept) 0.01718 0.14251 0.121
## scTrial -0.03851 0.03310 -1.164
##
## Correlation of Fixed Effects:
## (Intr)
## scTrial -0.227
- beágyazott random hatások (többféle megadási mód lehetséges):
mod_nested1 <- lmer(scRT ~ scTrial + (1 | Page) + (1 | Word),
data = lexdec_corr)
mod_nested2 <- lmer(scRT ~ scTrial + (1 | Page) + (1 | Word:Page),
data = lexdec_corr)
mod_nested3 <- lmer(scRT ~ scTrial + (1 | Page/Word),
data = lexdec_corr)
summary(mod_nested1)
## Linear mixed model fit by REML ['lmerMod']
## Formula: scRT ~ scTrial + (1 | Page) + (1 | Word)
## Data: lexdec_corr
##
## REML criterion at convergence: 4363.8
##
## Scaled residuals:
## Min 1Q Median 3Q Max
## -2.2557 -0.6725 -0.1447 0.4817 4.4651
##
## Random effects:
## Groups Name Variance Std.Dev.
## Word (Intercept) 0.07730 0.2780
## Page (Intercept) 0.08711 0.2951
## Residual 0.84531 0.9194
## Number of obs: 1594, groups: Word, 79; Page, 10
##
## Fixed effects:
## Estimate Std. Error t value
## (Intercept) 0.01154 0.10111 0.114
## scTrial -0.04445 0.02333 -1.905
##
## Correlation of Fixed Effects:
## (Intr)
## scTrial 0.000
summary(mod_nested2)
## Linear mixed model fit by REML ['lmerMod']
## Formula: scRT ~ scTrial + (1 | Page) + (1 | Word:Page)
## Data: lexdec_corr
##
## REML criterion at convergence: 4363.8
##
## Scaled residuals:
## Min 1Q Median 3Q Max
## -2.2557 -0.6725 -0.1447 0.4817 4.4651
##
## Random effects:
## Groups Name Variance Std.Dev.
## Word:Page (Intercept) 0.07730 0.2780
## Page (Intercept) 0.08711 0.2951
## Residual 0.84531 0.9194
## Number of obs: 1594, groups: Word:Page, 79; Page, 10
##
## Fixed effects:
## Estimate Std. Error t value
## (Intercept) 0.01154 0.10111 0.114
## scTrial -0.04445 0.02333 -1.905
##
## Correlation of Fixed Effects:
## (Intr)
## scTrial 0.000
summary(mod_nested3)
## Linear mixed model fit by REML ['lmerMod']
## Formula: scRT ~ scTrial + (1 | Page/Word)
## Data: lexdec_corr
##
## REML criterion at convergence: 4363.8
##
## Scaled residuals:
## Min 1Q Median 3Q Max
## -2.2557 -0.6725 -0.1447 0.4817 4.4651
##
## Random effects:
## Groups Name Variance Std.Dev.
## Word:Page (Intercept) 0.07730 0.2780
## Page (Intercept) 0.08711 0.2951
## Residual 0.84531 0.9194
## Number of obs: 1594, groups: Word:Page, 79; Page, 10
##
## Fixed effects:
## Estimate Std. Error t value
## (Intercept) 0.01154 0.10111 0.114
## scTrial -0.04445 0.02333 -1.905
##
## Correlation of Fixed Effects:
## (Intr)
## scTrial 0.000