Exercise 1

letters
##  [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q"
## [18] "r" "s" "t" "u" "v" "w" "x" "y" "z"
s <- c(letters)
first.five <-s[1:5]
first.five
## [1] "a" "b" "c" "d" "e"
last.five <- s[(length(letters)-4):length (letters)]
last.five
## [1] "v" "w" "x" "y" "z"

Exercise 2

every.second <- s[seq(2,26,2)]
every.second
##  [1] "b" "d" "f" "h" "j" "l" "n" "p" "r" "t" "v" "x" "z"

Exercise 3

s <- c(letters)
object.t <- c("t")
log.vec <- object.t ==s
log.vec
##  [1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
## [12] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE  TRUE FALSE FALSE
## [23] FALSE FALSE FALSE FALSE
which(log.vec)
## [1] 20

Exercise 4

vowels <- c("a", "e", "i", "o", "u")
log.vec2 <- s %in% vowels
log.vec2
##  [1]  TRUE FALSE FALSE FALSE  TRUE FALSE FALSE FALSE  TRUE FALSE FALSE
## [12] FALSE FALSE FALSE  TRUE FALSE FALSE FALSE FALSE FALSE  TRUE FALSE
## [23] FALSE FALSE FALSE FALSE
which(log.vec2)
## [1]  1  5  9 15 21

Exercise 5

seeds <- c(6, 10, 243, 12, 43, 20, 34, 18, 24, 20)
pirates <- c("Emmanuel", "Alissa", "Lucia", "Marcel", "Florian", "Nadiia", "Yvonne", "Florina", "Xu", "Zoe")
over.thirty <- seeds > 30
over.thirty
##  [1] FALSE FALSE  TRUE FALSE  TRUE FALSE  TRUE FALSE FALSE FALSE
sum(over.thirty)
## [1] 3
mean(over.thirty)
## [1] 0.3

Exercise 6

less.fourty <- seeds < 40
sd(less.fourty)
## [1] 0.421637

Exercise 7

max.seeds <- max(seeds)
max.seeds
## [1] 243
log.most.seeds <- seeds >= max.seeds
log.most.seeds
##  [1] FALSE FALSE  TRUE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
name.most <- which (log.most.seeds)
name.most
## [1] 3
pirates[name.most]
## [1] "Lucia"

Exercise 8

over.fifty <- seeds > 50
over.fifty
##  [1] FALSE FALSE  TRUE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
pirate.number <- which(over.fifty)
pirates[pirate.number]
## [1] "Lucia"

Exercise 9

min.standard <- mean(seeds) - sd(seeds)*2
min.standard
## [1] -99.2736
max.standard <- mean(seeds) + sd(seeds)*2
max.standard
## [1] 185.2736
high <- seeds >max.standard
high
##  [1] FALSE FALSE  TRUE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
low <- seeds < min.standard
low
##  [1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
is.outlier <-  high | low
is.outlier
##  [1] FALSE FALSE  TRUE FALSE FALSE FALSE FALSE FALSE FALSE FALSE

There ist 1 outlier.

Exercise 10

no.outlier <- is.outlier == F
f <- which(no.outlier)
mean.no.outlier <- mean (seeds[f])
mean.no.outlier
## [1] 20.77778
median.no.outlier <- median (seeds[f])
median.no.outlier
## [1] 20

Exercise 11

katharina <- c("Breaking Bad", "Game of Thrones", "The Simpsons")
tani <- c("Orange is the New Black", "Game of Thrones", "House of Cards")
alexander <- c("The Walking Dead", "Game of Thrones", "True Detective")
sarah <- c("Mad Men", "My Little Pony", "House of Cards")
rebekka <- c("Game of Thrones", "Gotham", "Breaking Bad")

responses <- c(katharina, tani, alexander, sarah, rebekka)
responses
##  [1] "Breaking Bad"            "Game of Thrones"        
##  [3] "The Simpsons"            "Orange is the New Black"
##  [5] "Game of Thrones"         "House of Cards"         
##  [7] "The Walking Dead"        "Game of Thrones"        
##  [9] "True Detective"          "Mad Men"                
## [11] "My Little Pony"          "House of Cards"         
## [13] "Game of Thrones"         "Gotham"                 
## [15] "Breaking Bad"

Exercise 12

favs <- unique(responses)
favs
##  [1] "Breaking Bad"            "Game of Thrones"        
##  [3] "The Simpsons"            "Orange is the New Black"
##  [5] "House of Cards"          "The Walking Dead"       
##  [7] "True Detective"          "Mad Men"                
##  [9] "My Little Pony"          "Gotham"

Exercise 13

number.favs <- table(responses)
number.favs
## responses
##            Breaking Bad         Game of Thrones                  Gotham 
##                       2                       4                       1 
##          House of Cards                 Mad Men          My Little Pony 
##                       2                       1                       1 
## Orange is the New Black            The Simpsons        The Walking Dead 
##                       1                       1                       1 
##          True Detective 
##                       1

Exercise 14

show <- c("Orange is the New Black")
show
## [1] "Orange is the New Black"
show %in% responses
## [1] TRUE
sum(show == responses) > 0
## [1] TRUE

Exercise 15

house <- c("House of Cards")
sum(house == responses)
## [1] 2
l<- house == responses
l
##  [1] FALSE FALSE FALSE FALSE FALSE  TRUE FALSE FALSE FALSE FALSE FALSE
## [12]  TRUE FALSE FALSE FALSE