For tutors
Assign coding problems and quizzes to your class
Two banks of practice material: coding problems solved in R, and multiple-choice quiz questions. Both randomise per student, so everyone gets the same question with different numbers. Anyone can practise from both, free. Tutor access adds assigning to a class and seeing who has done what.
What's in the banks
Both are tagged by topic and difficulty, and browse the same way.
Coding problems
Written in R and solved in the browser. Students assign the answer to a named variable, run their code to check it, and submit for instant feedback. Topics run from descriptive statistics through regression, causal inference and machine learning.
Browse coding problems →Quiz questions
Multiple choice, generated fresh for each student from the same template. The numbers, the correct answer and the wrong options all change, so answers can't be copied between students.
Browse quiz questions →See the randomisation
The same quiz question, generated for a different student each time you press the button.
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Options shown as plain text. In a real quiz they're selectable and marked automatically.
What a coding problem looks like
A real problem from the bank, with the editor and console a student sees.
Given numeric vectors x and
y, compute the sample covariance
with denominator n − 1 (like
cov()). Return a single numeric
cov_xy without using the inbuilt
function cov().
Editor
n <- length(x) mx <- sum(x) / n my <- sum(y) / n cov_xy <- sum((x - mx) * (y - my)) / (n - 1)
Console
> cov_xy
[1] 14.0725
After submitting
Who can do what
The same three levels apply to both banks.
No account
Browse and solve most of both banks. Your history starts when you create an account.
Free account
Everything above, plus the items marked sign in to unlock, your solve history, and progress across topics.
Tutor access
Build problem sets and quizzes, assign them to a class, set deadlines, and see who has completed what. Every request is approved by hand.
Request tutor access
Tutor access covers both banks: you can assign coding problems and quizzes to the same class, set deadlines, and see who has completed what.
Every request is reviewed by a person. We check you teach the course, since tutor accounts set assessed work and see student results.
Tell us your institution, what you teach, and roughly how many students.