| lexdec | R Documentation |
Lexical decision latencies elicited from 21 subjects for 79 English concrete nouns, with variables linked to subject or word.
data(lexdec)
A data frame with 1659 observations on the following 28 variables.
Subjecta factor for the subjects.
RTa numeric vector for logarithmically transformed reaction times.
Triala numeric vector for the rank of the trial in the experimental list.
Sexa factor with levels F (female) and M (male).
NativeLanguagea factor with levels English and Other, distinguishing
between native and nonnative speakers of English.
Correcta factor with levels correct and incorrect coding whether
the word was correctly responded to as a word rather than a nonword.
PrevTypea factor with levels nonword and word coding whether the
item presented at the preceding trial was a word or a nonword.
PrevCorrecta factor with levels correct and incorrect coding whether
the preceding item elicited a correct response.
Worda factor with 79 words as levels.
Frequencya numeric vector with logarithmically transformed lemma frequencies as available in the CELEX lexical database.
FamilySizea numeric vector with the log-transformed count of a word's morphological family members.
SynsetCounta numeric vector with the log-transformed count of synonym sets in WordNet in which the word is listed.
Lengtha numeric vector for the word's length in letters.
Classa factor for the semantic category of the word's referent, with levels
animal and plant.
FreqSingulara numeric vector with the frequency in CELEX of the singular form.
FreqPlurala numeric vector with the frequency in CELEX of the plural form.
DerivEntropyShannon's entropy calculated over the frequency distribution of a word's family members.
Complexa factor coding morphological complexity with levels complex and
simplex.
rInfla numeric vector for the log of the ratio of the singular to the plural frequency.
meanRTa numeric vector for the by-item mean reaction time averaged over subjects.
SubjFreqa numeric vector for the by-item mean subjective frequency estimate averaged over subjects.
meanSizea numeric vector for the by-item mean size rating averaged over subjects.
meanWeighta numeric vector for the by-item mean weight rating averaged over subjects.
BNCwa numeric vector with the logarithmically transformed frequency in the written part of the British National Corpus.
BNCca numeric vector with the logarithmically transformed frequency in the context-governed part of the British National Corpus.
BNCda numeric vector with the logarithmically transformed frequency in the demographic part of the British National Corpus.
BNCcRatioa numeric vector with the log of the ratio of the (absolute) frequencies in the context-governed and written parts of the British National Corpus, normalized for the differences in corpus size.
BNCdRatioa numeric vector with the log of the ratio of the (absolute) frequencies in the demographic and written parts of the British National Corpus, normalized for the differences in corpus size.
Data collected with Jen Hay, University of Canterbury, Christchurch, New Zealand, 2004.
## Not run:
data(lexdec)
require(lme4)
require(lmerTest)
require(optimx)
lexdec.lmer = lmer(RT ~ 1 + Correct + Trial + PrevType * meanWeight +
Frequency + NativeLanguage * Length + (1|Subject) + (1|Word),
control=lmerControl(optimizer="optimx",optCtrl=list(method="nlminb")),
data = lexdec)
summary(lexdec.lmer)
# random slopes
lexdec.lmerA = lmer(RT ~ 1 + Correct + Trial + PrevType * meanWeight +
Frequency + NativeLanguage * Length + (Trial|Subject) + (1|Word),
control=lmerControl(optimizer="optimx",optCtrl=list(method="nlminb")),
data = lexdec)
anova(lexdec.lmer, lexdec.lmerA)
lexdec.lmerB = lmer(RT ~ 1 + Correct + Trial + PrevType * meanWeight +
Frequency + NativeLanguage * Length + (Trial|Subject) +
(Length|Subject) + (1|Word), data = lexdec,
control=lmerControl(optimizer="optimx",optCtrl=list(method="nlminb")))
anova(lexdec.lmerA, lexdec.lmerB)
# model criticism
qqnorm(resid(lexdec.lmerB))
lexdec.lmerC = lmer(RT ~ 1 + Correct + Trial + PrevType * meanWeight +
Frequency + NativeLanguage * Length +
(Trial|Subject) + (Length|Subject) + (1|Word),
data = lexdec[abs(scale(resid(lexdec.lmerB)))<2,],
control=lmerControl(optimizer="optimx",optCtrl=list(method="nlminb")))
qqnorm(resid(lexdec.lmerC))
# p values
summary(lexdec.lmerC)
## End(Not run)
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