In doomlab/learnSTATS: Introduction to Statistics (ANLY 500)

library(learnr)
library(learnSTATS)
knitr::opts_chunk$set(echo = FALSE)

Introduction to R Class Assignment

In this example, you will practice your R skills! You will map key concepts of variable types to objects types and begin interacting in a console as part of this tutorial. The learning objectives include:

• Understand logical operators
• Work with variables, vectors, matrices, and dataframes
• Write your own functions
• Load libraries and files

Introduction R Video Part 1

The following videos are provided as a lecture for the class material. You can view the lecture notes within R using vignette("Introduction-to-R", "learnSTATS"). You can skip these pages if you are in class to go on to the assignment.

Introduction R Video Part 2

Introduction R Video Part 3

Exercises

In this next section, you will answer questions using the R code blocks provided. Be sure to use the solution option to see the answer if you need it!

Please enter your name for submission. If you do not need to submit, just type anything you'd like in this box.

question_text(
  "Student Name:",
  answer("Your Name", correct = TRUE),
  incorrect = "Thanks!",
  try_again_button = "Modify your answer",
  allow_retry = TRUE
)

Logical Operators

Use logical operations to get R to agree that "two plus two equals 5" is FALSE.

2 + 2 == 5

Use logical operations to test whether 8 ^ 13 is less than 15 ^ 9.

8 ^ 13 < 15 ^ 9

Simple Variables

Create a variable called potato whose value corresponds to the number of potatoes you've eaten in the last week. Then print out the value of potato.

#there are a lot of right answers!
potato <- 15

Calculate the square root of potato using the sqrt() function. Print out the value of potato again to verify that the value of potato hasn't changed. Note that potato has been set to 15 for this question.

potato <- 15

sqrt(potato)
potato

Reassign the value of potato to potato * 2. Print out the new value of potato to verify that it has changed.

potato <- 15

potato <- potato * 2
potato

Create three new variables:

• Create a string (character variable), and name that variable charVar.
• Create a logical variable, and name that variable logicalVar.
• Create a variable that contains a missing value NA, and name that variable missingVar.
• Use class() to verify that each variable is the right type.

charVar <- "cheese"
logicalVar <- TRUE
missingVar <- NA
class(charVar)
class(logicalVar)
class(missingVar)

Vectors

Create a numeric vector with three elements using c().

#lots of right answers!
c(1,2,3)

Create a character vector with three elements using c().

#lots of right answers!
c("this", "is", "characters")

Create a numeric vector called age whose elements contain the ages of three people you know. Add the names of these people using names(age).

#lots of right answers!
age <- c(34, 38, 27)
names(age) <- c("scott", "abby", "katy")

Use "indexing by number" to get R to print out the first element of Orange$circumference.

data("Orange")

data("Orange")
Orange$circumference[1]

Use logical indexing to return all the circumferences of Orange trees greater than 100.

Orange$circumference[]

Orange$circumference[Orange$circumference > 100]

Dataframes

Load the airquality dataset. Use the $ method to print out the Wind variable in airquality.

data("airquality")
airquality$Wind

Print out only the first 10 cases (rows) in the airquality dataset. Hint: typing c(1,2,3,4,5,6,7,8,9,10) is tedious. R allows you to use 1:10 as a shorthand method!

airquality[1:10 , ]

Use logical indexing to print out all days in airquality where the Ozone level was higher than 20.

airquality[airquality$Ozone > 20 , ]

Use subset() to do the same thing. Notice the difference in the output.

subset(airquality, Ozone > 20)

Use the length() function to determine the number of observations in the airquality dataframe.

#remember that number of rows needs to be on a vector 
length(airquality$Ozone) 

Functions

Make a simple function to calculate x + 6.

addup <- function(x) { x + 6 }

Packages

Load the utils library.

library(utils)

Submit

On this page, you will create the submission for your instructor (if necessary). Please copy this report and submit using a Word document or paste into the text window of your submission page. Click "Generate Submission" to get your work!

encoder_logic()

encoder_ui()

doomlab/learnSTATS documentation built on June 9, 2022, 12:54 a.m.