r – Error in x[floor(d)] + x[ceiling(d)] : non-numeric argument to binary operator
r – Error in x[floor(d)] + x[ceiling(d)] : non-numeric argument to binary operator
The solution by jay.sf in the comment works. You would also need to use ggplot() when running your code to produce the boxplot, ie ggplot() + boxplot(viral_load ~ trial_arm, dataset)