Assignment 1

Question 1 (5 points)

Do the following in R:

• Assign 8 to p
• Assign 6 to q
• Swap the values of p and q. You are not allowed to directly assign values. You have to “swap” them!

# Write your answer here

Question 2 (10 points)

• Create a vector of the populations of the 10 largest cities in Turkey.
• Name your vector with the names of the cities.
• Print the names of the cities that have a population between 2 million and 3 million.

# Write your answer here

Question 3 (10 points)

• Create a matrix as follows:
  • First consists of numbers: {1,2,3,4,5,6}
  • Second row consists of numbers: {2,4,6,8,10,12}
  • Third row consists of numbers: {1,3,5,7,9,11}
  • Fourth row consists of the sum of the second and third rows
  • Fifth row consists of the division of the fifth row with the first row
• Swap the columns of the matrix so that the first row reads: {1,3,5,2,4,6}

# Write your answer here

Question 4 (10 points)

• Create a factor from the following vector: {"red", "red", "blue", "brown", "green", "blue", "red", "green", "green", "brown", "red", "blue"}
• Display the frequencies of each factor value (level)
• Re-name "red" as "purple"
• Display the number of “purples”

# Write your answer here

Question 5 (20 points)

• Create a data frame for the following girls. You must choose the correct column types:
  • Canan is 24 years old, blonde, 170cm and 56kgs. She is married.
  • Deniz is 35 years old, has brown hair, 173cm and 61kgs. She is married.
  • Eda is 21 years old, has brown hair, 156cm and 45kgs. She is not married.
  • Fatma is 40 years old, has black hair, 164cm and 60kgs. She is married.
  • Gonca is 33 years old, blonde, 182cm and 65kgs. She is not married.
  • Hilal is 45 years old, has black hair, 165cm and 58kgs. She is married.
  • Lale is 38 years old, has black hair, 175cm and 59kgs. She is not married.
  • Mine is 28 years old, has brown hair, 190cm and 71kgs. She is not married.
• Answer the following questions based on this dataframe:
  • What is the average age of the group?
  • How many girls are above the average height?
  • What is the most frequent hair color?
  • What is the average height of girls above 60kgs?
  • Compare the height/weight ratio of married and single girls. Which is higher?

# Write your answer here

Question 6 (15 points)

• Given the below vector, compute its mean without using any functions.

# Do not change the two lines below
set.seed(1024)
v <- runif(100, 1, 20) + rnorm(100, 1, 3)

# Compute the mean of v below

Question 7 (20 points)

• Write a function that takes two numeric vectors and returns a matrix as follows:

# Example:
> a <- c(1,3,5)
> b <- c(20, 40, 60)

> c <- your_function(a, b)
> c

     [,1] [,2] [,3]
[1,]   21   41   61
[2,]   23   43   63
[3,]   25   45   65

# Write your answer here

Question 8 (20 points)

• Write a function that takes a numeric vector vec and a numeric variable val, and returns TRUE if val exists in vec, and otherwise returns FALSE. You are not allowed to use %in% or any other functions present in R.

# Write your answer here