Activity: Data wrangling across columns and functions

Instructions:

• Work with a neighbor to answer the following questions
• To get started, download the class activity template file
• When you are finished, render the file as an HTML and submit the HTML to Canvas (let me know if you encounter any problems)

Student grades

You are a TA for a statistics course. The instructor of the course is interested in assessing how students performed on each assignment in the class.

You are provided with a CSV file (student_grades.csv), from Canvas, containing the grades for each student on each assignment in the course. Here are the instructions the professor gives you:

• There are 6 homeworks, 2 midterms, a final exam, and a project
• Each homework is scored out of 10. All other assignments are scored out of 100
• If a student did not submit an assignment, it is marked as NA in the CSV file. These missing assignments should receive a score of 0

The data can be imported into R with the following code:

library(tidyverse)

student_grades <- read_csv("https://sta279-f25.github.io/data/student_grades.csv")

Questions

Your answers to these questions should involve functions like starts_with, where, across, etc. You should not list all of the homework columns explicitly, e.g.

1. What was the average exam score for each midterm?

2. What fraction of students failed each midterm (a grade less than 60%)?

3. What was the average score for each homework, if you ignore missing submissions?

4. What was the average score for each homework, if you treat missing assignment as 0? Hint: One approach could use the replace_na function

5. For each homework assignment, how many students failed to submit?