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

1.5-54
## [1] -52.5
1.5*15
## [1] 22.5
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
round(mean(scores),2)
## [1] 73.28
avg<-round(mean(scores),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
## [1]  TRUE  TRUE  TRUE  TRUE  TRUE FALSE FALSE  TRUE  TRUE
length(scores[scores>avg])
## [1] 7
#create a new set of scores, call it new_scores.  The new list should include elements 2 to 6
scores[2:6]
## [1] 100.0  91.0  95.0  81.5   0.0
new_scores<-scores[2:6]
new_scores
## [1] 100.0  91.0  95.0  81.5   0.0

Problem 3: Read section 2.3

# Create a vector with the number 1 repeated 5 times. Print it
rep(1,times=5)
## [1] 1 1 1 1 1
num_vec<-rep(1,times=5)
num_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
1:10
##  [1]  1  2  3  4  5  6  7  8  9 10
seq(from=1,to=10,by=2)
## [1] 1 3 5 7 9
seq_vec<-seq(from=1,to=10,by=2)
seq_vec
## [1] 1 3 5 7 9
# Create a vector by repeating a sequence from 1 to 3, 2 times. call it
rep(1:3,times=2)
## [1] 1 2 3 1 2 3
rep_vec<-rep(1:3,times=2)
rep_vec
## [1] 1 2 3 1 2 3

Problem 4

# Create a vector with different class types
c(1, "two", 3.0, TRUE, 2)
## [1] "1"    "two"  "3"    "TRUE" "2"
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