Homework 1

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

numbers <- c(1.5, 15, 0, 54, 23)

##Pick two numbers, for example 15 and 23

subtruction

subtruction <- 23-15

multiplication

multiplication <- 15*23

square root

sqrt_15 <- sqrt(15)
sqrt_23 <- sqrt(23)

Print results

subtruction

## [1] 8

multiplication

## [1] 345

sqrt_15

## [1] 3.872983

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 <- round(mean(scores), 2)
avg_score

## [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
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
scores[2:6]

## [1] 100.0  91.0  95.0  81.5   0.0

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)
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_seq <- seq(from = 1, to = 10, by = 2)
my_seq

## [1] 1 3 5 7 9

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

## [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