atheobold
commented
4 years ago @linqinyu thank you for voicing some suggestions for the Introduction to R lesson! Currently, the lesson's exercise (that follows the introduction of round()) asks learners to explore the help file for round. The ceiling(), floor(), and trunc() functions are included in this help file, and the exercise prompts learners to look for functions that are similar to round. To me, this prompting is sufficient for introducing these additional rounding functions.
Additionally, because R has many tools for working with missing data that have been coded as NAs, I would prefer to stick to advocating for researchers to code their data in this way. Although I have seen researchers need to recode data where missing values were coded as 999 to NA values, this change would not fit the context of the exploration of missing values in this section.
qinyun-lin
Two small suggestions, see if this makes sense! (1) For the part of "Functions and their arguments", it might be helpful to quickly go through different rounding functions (i.e., ceiling, floor, and trunc), after the function "round". (2) For the "Missing data" part, one example that might be useful & meaning to add is how to change all missing values into a particular value, such as 999.