Practice 2 Answers

PUBH 523/623

Author

Nicky Wakim

Modified

July 15, 2026

Questions

Question 1: Your First Practice .qmd

In Lesson 8, we walked through the three components of a .qmd file: the YAML header, text, and code chunks. In this question, you will demonstrate that you can create, edit, and render a .qmd file correctly.

Part A: Downloading the practice file

WarningTask

Download this practice .qmd from the course GitHub repository, rename it, and save it in your course folder.

  1. Download practice_02.qmd from GitHub.
  2. Rename the file to Lastname_Firstinitial_Practice_02.qmd (or lastname_firstinitial_practice_02.qmd), replacing with your actual last name and first initial.
  3. Save it inside your practice/ folder. You may create a practice_02/ subfolder if you prefer.

Answer:

No answer given, for completion only.

Part B: Check your YAML header

WarningTask

Scroll to the very top of this file and update the YAML header:

  • Replace "Your name here" in author: with your actual name.
  • Confirm that date-modified: "today" is present so the date updates automatically each time you render.

Render the document and confirm your name and today’s date appear at the top of the HTML output.

Answer:

No answer given, for completion only.

Part C: Add a heading and paragraph

WarningTask

Directly below this callout box, add:

  1. A level 3 heading (###) with a title of your choice (something about yourself or why you are taking this course)
  2. A short paragraph (2–4 sentences) of text (can be gibberish) under that heading

You can use the Source editor or the Visual Editor.

Answer:

Not given

Part D: Code chunk options

WarningTask

The code chunk below calculates the mean of a small vector. Adjust the chunk options so that:

  • The code is hidden in the rendered output (results still show)
  • Warnings are suppressed

Answer:

echo and warning control these options.

Part E: Render and confirm

WarningTask

Render this document to HTML and confirm all of the following:

  • Your screenshot from Question 1 Part B appears
  • Your heading and paragraph from Part C appear
  • The code chunk in Part D shows the result but not the code

Answer:

No answer given, for completion only.

Question 2: Set Up Your Course Folder

In our lesson on folder and file organization (L7), we learned that every project should live in one well-organized folder. In this question, you will create that folder and use it for the rest of the course.

Part A: Create the folder structure

WarningTask

On your computer, create a folder called PUBH_523_26Su or PUBH_623_26Su somewhere that makes sense (your Documents folder, OneDrive, etc.). Inside it, create the following subfolders (feel free to change some of the subfolders if you have a preferred organization):

PUBH_523_26Su/
├── admin/
├── data_lessons/
├── data_practice/
├── data_project/
│   ├── data_raw/
│   └── data_processed/
├── lessons/
├── practice/
├── project/
└── README.txt

Answer:

No answer given, for completion only.

Part B: Take a screenshot and insert it here

WarningTask

Take a screenshot of your PUBH_523_26Su folder open in your file browser (Finder on Mac, File Explorer on Windows) so that the subfolders are visible and insert in this .qmd.

Answer:

Here is the image path to my screenshot:

![](../images_practice_solns/folder_screenshot.png)

You will need to make sure your file path takes you to your screenshot.

Question 3: Packages

Part A: Load the course packages

WarningTask

In Lesson 9, we learned to use pacman::p_load() to install and load packages in one step. In the code chunk below, use pacman::p_load() to load all of the following packages:

tidyverse, here, readxl, haven, writexl, janitor, rstatix, gt, gtsummary, naniar

Answer:

No answer given, for completion only.

Part B: What does each package do?

WarningTask

Fill in the table below. Each package belongs to one of three categories from Lesson 9: loading/saving data, summarizing/visualizing data, or wrangling data. Note one specific thing each package is used for.

Answer:

Here is the table with select rows filled out

Package Category One thing it is used for
here
readxl Loading/saving data Read Excel (.xlsx) files into R
haven
janitor
gtsummary
dplyr (part of tidyverse)
ggplot2 (part of tidyverse) Summarizing/visualizing data Create data visualizations using a layered syntax

Note: other valid answers exist for each package, the above are examples.

Part C: Install vs. load

WarningTask

A classmate wrote the following at the top of their .qmd file. Identify the problem and explain how to fix it.

install.packages("tidyverse")
library(tidyverse)

What is wrong with putting install.packages() inside a .qmd, and what should they do instead?

Answer:

Not given

Question 4: Create Your R Project

We learned that an R Project (.Rproj file) sets the working directory automatically so you never need setwd().

Part A: Create the project

WarningTask

Create an R Project inside your existing PUBH_523_26Su folder and open this .qmd from within it.

Answer:

No answer given, for completion only.

Part B: Confirm the working directory

WarningTask

Run the following code in your Console (not in a rendered chunk) and paste the output in the space below.

getwd()

Answer:

The output should be the full path to your PUBH_523_26Su (or PUBH_623_26Su) folder.

Part C: Does the working directory match?

WarningTask

Now run getwd() inside a code chunk and render the document. Does the output match what you pasted in Part B? Write 1–2 sentences explaining what you observe.

Answer:

No, the output will not match.

Part D: Why not setwd()?

WarningTask

In 1–2 sentences, explain why you should not use setwd() in your .qmd files, and what you should do instead.

Answer:

Not given. Think about absolute file paths vs relative file paths.

Question 5: Using here() for file paths

Part A: Explore here()

WarningTask

Run the following code chunk and render the document. Does the output match your getwd() output from Question 4 Part B? Explain in 1 sentence why they match.

Answer:

Should match!

Part B: Build a file path with here()

WarningTask

Imagine you saved a data file called survey_data.csv in your data_practice/ folder. Fill in the here() call below to build the path to that file, then run the chunk to confirm the path looks correct.

Which path style do you prefer and why? (1–2 sentences)

Answer:

Not given

Part C: Console vs. render

WarningTask

Explain in 2–3 sentences: what problem does here() solve that an R Project alone does not fully fix? Think about what happens when you run code in the Console versus when you render a .qmd.

Answer:

Not given