library(MASS)


# dB-RMS Energie zum Mittelpunkt
avrms = dcut(vowlax.rms, .5, prop=T)

temp = vowlax.l == "a" & vowlax.spkr=="68"

dat = cbind(dcut(vowlax.fdat[temp,1], .5, prop=T), 
avrms[temp], dur(vowlax[temp,]))

colnames(dat) = c("F1", "RMS", "d")
dat = data.frame(dat)
attach(dat)
par(mfrow=c(1,2))
plot(RMS, F1)
plot(d, F1)
# vielleicht den Ausresisser dB < 55 entfernen
temp = RMS < 60
sum(temp)
RMS = RMS[!temp]
F1 = F1[!temp]
d = d[!temp]
plot(RMS, F1)
plot(d, F1)


o = lm(F1 ~ RMS+d)
summary(o)
stepAIC(o)

# Normalverteilung pruefen
shapiro.test(resid(o))
# Konstante Varianz?
plot(resid(o))
# Autokorrelation?
acf(resid(o))
plot(o, 4)