zeit = as.numeric(rownames(bridge))

# 2.1
zeit[bridge[,3] > bridge[,2]]

# 2.2
zeit[bridge[,2] < 60]

# 2.3
zeit[bridge[,2] < 5 | bridge[,3] < 5]

# 2.4
sum(bridge[,3] > bridge[,1])

# 2.5
zeit[bridge[,2] > 60 & bridge[,2] < 100]

# 2.6
zeit[ bridge[,2] - bridge[,3] < 30 ]

# 4.
# 4.1
nrow(vowlax.df)

# 4.2
ncol(vowlax.df)

# 4.3
vowlax.df[1:5,]

# 4.4
vowlax.df[phonetic=="I",]

# 4.5
sum(F2 < 1800 & phonetic %in% c("I", "E"))

# 4.6
vowlax.df[phonetic == "I" & bark(F3) - bark(F2) < 1,]

# 4.7
# entweder
vowlax.df[dur == max(dur),2:3]
# oder
cbind(F2, F3)[dur == max(dur),]

# 4.8
# entweder
vowlax.df[dur > 100 & f0 < 90,4:5]

# oder
cbind(f0, rms)[dur > 100 & f0 < 90,]

# 4.9
table(phonetic[F1 > 400 & F2 < 1600])

# 4.10
word[ F3 - F2 > 900 & phonetic == "I"]