Homework2

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

# Making the data set as a vector
Problem_1_data <- c(1.5, 15, 0, 54, 23)

#Subtraction
Problem_1_data[1] - Problem_1_data[5]

## [1] -21.5

#Multiplication
Problem_1_data[1] * Problem_1_data[5]

## [1] 34.5

#square root
sqrt(Problem_1_data[1])

## [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
mean(scores)

## [1] 73.27778

#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 of scores, call it new_scores.  The new list should include elements 2 to 6
new_scores <- scores[c(2, 6)]

Problem 3: Read section 2.3

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

## [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
seq_1_10 <- seq(1,10,by=2)
seq_1_10

## [1] 1 3 5 7 9

# Create a vector by repeating a sequence from 1 to 3, 2 times. call it
seq_1_3_2x <- rep(1:3, times = 2)
seq_1_3_2x

## [1] 1 2 3 1 2 3

Problem 4

# Create a vector with different class types
mixed_vector <- c(1, "two", 3.0, TRUE, 2)
mixed_vector

## [1] "1"    "two"  "3"    "TRUE" "2"

# Check the class of the vector
class(mixed_vector)

## [1] "character"

## Coerce to numeric and print it 
numeric_vector <- as.numeric(mixed_vector)

## Warning: NAs introduced by coercion

numeric_vector

## [1]  1 NA  3 NA  2