R Basics

You can insert an R code chunk into an R Markdown document by using a keyboard shortcut. The default keyboard shortcut to insert an R code is:

Windows/Linux: Ctrl + Alt + I Mac: Command + Option + I

Make sure to comment on your code using #

Problem 1:

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

.Subtraction .Multiplication .square root

54 - 23
## [1] 31
54 * 23
## [1] 1242
sqrt (23)
## [1] 4.795832

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
avg_score <- mean(scores)

avg_scrore_rounded <-  round (avg_score, 2)

#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 > avg_score
## [1]  TRUE  TRUE  TRUE  TRUE  TRUE FALSE FALSE  TRUE  TRUE
sum (scores>avg_score)
## [1] 7
#Create a new set called new_scores that includes the elements from indices 2 to 6 of the scores vector

new_scores <- 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_vec <- rep(1, times = 5)
print(my_vec)
## [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_vec1 <- seq (from = 1, to = 10, by = 2)
 print(my_vec1)
## [1] 1 3 5 7 9
# Create a vector by repeating a sequence from 1 to 3, 2 times. Print it.

my_vec2 <- rep (1:3, times = 2)
print(my_vec2)
## [1] 1 2 3 1 2 3

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 
as.numeric(mixed_vector)
## Warning: NAs introduced by coercion
## [1]  1 NA  3 NA  2
print(as.numeric(mixed_vector))
## Warning in print(as.numeric(mixed_vector)): NAs introduced by coercion
## [1]  1 NA  3 NA  2