Quiz Policy

There will be a total of eight quizzes in STAT 385. Quizzes are administered through PrairieLearn.

To access the course’s PrairieLearn content, simply navigate to prairielearn.org and add the course.


Quizzes will be low-stakes, unlimited attempt assessments. That is, there is no penalty for submitting incorrect answers, and your score can only go up, never down. These quizzes will serve as practice for the exam. No quizzes will be dropped. Instead, there will be opportunity to earn buffer points with each quiz. Buffer points will allow you to obtain over 100% for a particular assignment, but your percentage on quizzes overall cannot exceed 100%.

The buffer point and late submission details can be seen in the details of each quiz on PrairieLearn. As an example, consider Quiz 01:

  • 105% Credit: Thursday, September 8, 11:59 PM
  • 100% Credit: Thursday, September 15, 11:59 PM
  • 75% Credit: Thursday, September 22, 11:59 PM

To obtain the 105% credit, you must achieve a raw score of 100% before the “due” date for 105% credit. For quiz “due” dates, we will generally refer to the date to obtain 105% credit.

Unless otherwise specified, assume you cannot load any external R libraries or source any additional files. The following “words” are considered illegal, and cannot be found anywhere in code submitted to the autograder unless specifically allowed in a particular exercise:

  • library
  • require
  • source
  • ::

Quizzes will be released one week before the 105% credit deadline, at the latest.

Tips and Tricks

  • Before submitting to the autograder, you should run your code locally and verify that it produces the expected output.
  • If you are asked to write a function, you should test it locally by supplying potential values for each argument.
  • We do not recommend editing code directly in PrairieLearn. It is highly recommend that you edit your code using a proper text editor such as the one included in the RStudio IDE. It would also be wise to keep local copies of your work.
  • Unless a question notes otherwise, you do not need to defend against improper input to your functions. That is, you can assume we will test your code with input that agrees with the descriptions of the arguments in the question statement.