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

## Subtracting 23 and 1.5 
23- 1.5
## [1] 21.5
## Multiplying 1.5 and 23
1.5 * 23
## [1] 34.5
## Square root of 54
sqrt(54)
## [1] 7.348469

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
mean (scores) 
## [1] 73.27778
mean_scores <- c(73.27778)
round (mean_scores, 2)
## [1] 73.28
#Find the Maximum and Minimum score
max(scores)
## [1] 100
min (scores)
## [1] 0
#Find how many scores were above the average, use coding for this
scores [scores > mean_scores]
## [1]  87.0 100.0  91.0  95.0  81.5  74.0  92.0
#Create a new set called new_scores that includes the elements from indices 2 to 6 of the scores vector
new_scores <- c(scores [2:6])

Problem 3:

Read section 2.3, then answer the following questions

# Create a vector with the number 1 repeated 5 times. Print it
my_seq <- (1:10)
my_seq2 <- rep (1, times = 5)
my_seq2
## [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
my_seq3 <-seq(from = 1, to = 10, by = 2)
my_seq3
## [1] 1 3 5 7 9
# Create a vector by repeating a sequence from 1 to 3, 2 times. Print it.
my_seq4 <-rep(1:5, times = 2)
my_seq4
##  [1] 1 2 3 4 5 1 2 3 4 5

Problem 4

mixed_vector <- c(1, "two", 3.0, TRUE, 2)

# Check the class of the vector
class(mixed_vector) 
## [1] "character"
## Coerce to numeric and print it 
mixed_vector2 <- as.numeric(mixed_vector)
## Warning: NAs introduced by coercion
mixed_vector2
## [1]  1 NA  3 NA  2