## 1. Load the dataset ape::carnivora.
## Hint: ?ape::carnivora
## 2. Pick a numerical variable with missing data, names a variable
## that contains NAs.
## Hint: ?anyNA
## 3. Calculate the number of observations in your chosen vector.
## Hints: ?is.na, ?`!`, sum(c(TRUE, FALSE, TRUE)) == 2
## 4. Why doesn't length work to count observations? What's the
## difference between (the correct answer for) 3. and what length
## returns?
## 5. Calculate mean/standard deviation/median/IQR by SuperFamily and
## then (separately) by Family for your chosen numerical variable.
## Hint: ?dplyr::group_by; ?dplyr::summarise
## 6. Make a box plot for your numerical variable by Family.
## 7. Plot your numerical variable by Family as a scatter plot, then
## add the mean and standard errors
## Hint: ?ggplot2::stat_summary
## 8. Even if you don't fully understand the bars sticking out of the
## mean, can you see any major differences in terms of measure of
## center, measure of spread, and measure of skew between the plots in
## 6. and 7.?