R Basics

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Problem 1:

  1. From set = {1.5, 15, 0, 54, 23}, pick two numbers and perform the Following Operations:

.Subtraction .Multiplication .square root

15 - 1.5
## [1] 13.5
## [1] 13.5
15 * 15
## [1] 225
## [1] 225
sqrt(1.5)
## [1] 1.224745
## [1] 1.224745

Problem 2

Suppose you have a set of numbers representing the assignments scores:

scores <- c(87,100, 91, 95, 81.5, 0, 39, 74, 92)

#Calculate the average of the scores, and round your answer to two decimal number
## [1] 87

#Find the Maximum and Minimum score
## Max [1] 100
## Min [1] 0
#Find how many scores were above the average, use coding for this
scores <- c(87,100, 91, 95, 81.5, 0, 39, 74, 92)
scores > 87
## [1] FALSE  TRUE  TRUE  TRUE FALSE FALSE FALSE FALSE  TRUE
## [1] FALSE  TRUE  TRUE  TRUE FALSE FALSE FALSE FALSE  TRUE

#Create a new set called new_scores that includes the elements from indices 2 to 6 of the scores vector
new_scores <- c(2,3,4,5,6)

Problem 3:

Read section 2.3, then answer the following questions

# Create a vector with the number 1 repeated 5 times. Print it
vector1 <- rep(1,5)
(vector1)
## [1] 1 1 1 1 1
## [1] 1 1 1 1 1

# Create a vector with a sequence of numbers from 1 to 10 with a step of 2. Print it
vector2 <- seq(1,10, by = 2)
(vector2)
## [1] 1 3 5 7 9
## [1] 1 3 5 7 9

# Create a vector by repeating a sequence from 1 to 3, 2 times. Print it.
vector3 <- rep(1:3, each = 2)
(vector3)
## [1] 1 1 2 2 3 3
## [1] 1 1 2 2 3 3

Problem 4

mixed_vector <- c(1, "two", 3.0, TRUE, 2)
vector4 <- c(10, "ABC", 1.5, 1:3, FALSE, 3)
(vector4)
## [1] "10"    "ABC"   "1.5"   "1"     "2"     "3"     "FALSE" "3"
# Check the class of the vector
class(vector4)
## [1] "character"
## [1] "character"
## Coerce to numeric and print it 
 as.numeric(vector4)
## Warning: NAs introduced by coercion
## [1] 10.0   NA  1.5  1.0  2.0  3.0   NA  3.0
## Warning: NAs introduced by coercion
## [1] 10.0   NA  1.5  1.0  2.0  3.0   NA  3.0